
Class 
Book 



~S3Z1 



Copyright N^. 



COPYRIGHT DEPOSnV 



CONCRETE 
ROADS AND PAVEMENTS 



By 
E. S. HANSON 

Affiliated Member Western Society of Engineers, Elitor The CEMK.vr Era, 
Author "Cement Pipe and Tile," etc. 



CHICAGO 

The Cement Era Publishing Company 

1913 



T t XT? 



Copyright 1913 by 
The Cement Era Publishing Company. 



;3'/9/to 



/ fh-^ 



>C1.A35417 



PREFACE. 

The essentials of a good roadway are far different 
at the present time from what thev were a few years 
ago. The introduction of high-speed vehicles, with 
tires covering a broad band of road and at the same 
time having well developed qualities of suction, has 
made necessary an entire revision of the science of 
roadmaking. 

Within the past few years the opinion has rapidly 
gained ground that the best material to meet these new 
conditions is concrete. A demand for information on 
this topic has thus been created, which it is the purpose 
of this volume to supply. 

The book is, in large part, frankly a compilation, 
and the effort has been to collect into convenient hand- 
book size everything of value which is so far known on 
the subject. 

It is hoped that the book will serve not only to 
stimulate construction of this class of roadways, but 
will also furnish roadmakers such specific data from 
the experience of others as to enable them to build the 
best class of concrete roads and pavements. 

E. S. Haxsox. 
Chicago, August 1, 1913. 



CONTENTS. 

Page. 
Chapter I. Concrete as a Road Material 5 

II. The Construction of Concrete Roadways... 20 

III. The Roads of Wayne County, Michigan 33 

IV. Cost of Concrete Roads in Illinois 50 

V. Other Examples of Concrete Roads 63 

VI. Some Data on City Pavements 82 

VII. Reinforced Concrete Pavements 97 

VIII. Concrete in Combination with Other Ma- 
terials 112 

IX. Patented Concrete Pavements 125 

X. The Theory and Practice of Joints 139 

XI. Some Tests on Concrete as a Roadway 
Material 146 

XII. Bridges and Culverts 159 

XIII. Sidewalks, Curbs and Gutters 177 

Appendix A. Specifications of National Association of 

Cement Users — Roads and Pavements. . . .179 

B. Wayne County Specifications 185 

C. Mason City Specifications 194 

D. Specifications of Illinois Highway Commis- 
sion 197 

E. Specifications for Blome Granitoid Pave- 
ment 202 

F. Specifications for Blome Granocrete Pave- 
ment 205 

G. Specifications for Bitustone Pavement 208 

H. Specifications for Dolarway Pavement 210 

I. Specifications for Hassamite 212 

J. Specifications for Bridges and Culverts. .. .214 

K. Specifications for Sidewalks 218 

L. Specifications for Curbs and Gutters 223 



Concrete Roads and Pavements 



CHAPTER I. 

Concrete as a Road ]\rATKRiAL. 

It is assiuncd at the outset that the reader is a 
])erson siifficieiitlj^ well informed to recognize the value 
of good roads and pavements, so that it will not be 
necessarv here to take up any arguments in behalf of 
the subject as a whole. Such work is much needed, 
to be sure ; but the one who takes up -, this book will 
already be a convert to this good roads movement, and 
will look to these pages, not for enthusiasm in the 
cause — which he already possesses — but for informa- 
tion and instruction regarding a type of roadway which 
has made rapid advancement within the past few years. 

AVithout further preliminaries, therefore, let us 
consider the essentials of a good roadway, so that we 
may see what the standards are by which a road must 
be measured. We shall then be in a position to apply 
the test to concrete roads and pavements and see how 
they measure up to the standard. 

The most scientific discussion of the qualities of 
a good roadway which the Avriter has seen is that of ^Er. 
Geo. W. Tillson, consulting engineer to the President 
of the Borough of Brooklyn, City of Xew York. This 
is given in the second edition of Mr. Tillson's volume 

(5) 



G Concrete Roads and Pavements. 

entitled ^^ Street Pavements and Paving Materials." 
Supposing the perfect pavement to liave a value of 
100, Mr. Tillson assigns various percentages to the 
different qualities, the list being as follows : 

Cheapness l-t 

Durability 21 

Ease of cleaning 15 

Resistance to traffic 15 

I^on-slipperiness 7 

Ease of maintenance 10 

Favorableness to travel 15 

Sanitariness l;3 



100 

This table was prepared primarily with city pave- 
ments in mind, and would perhaps be subject to some 
variation for country roads. ^Nevertheless, the writer 
is inclined to believe that it is just and fair, though he 
would possibly feel like giving a somewhat higher 
value to the item of maintenance. 

The application of this table of values to concrete 
roadways will show them to have decided advantages 
on every count. 

Cheapness. This relates primarily to first cost, 
leaving out of consideration for the time being any 
thought whatever of the ultimate, long-time, or real 
cost. That is, can a given community pay the initial 
cost of concrete without unduly drawing upon its pres- 
ent resources or too heavily mortgaging the future ? 

In answering this question, city pavements and 
country roads will have to be considered separately, 
inasmuch as in practically all localities the custom has 
been to accord the two an entirely different treatment. 



Concrele Roads and Pavements. 7- 

giving the city street a durable, well built pavement, 
while the country road has been content with almost 
any makeshift it could get. This is a condition which 
we believe will continue but a few years longer, ex- 
cept in very sparsely settled districts where the con- 
struction of permanent roads is out of the question ; 
but so long as it remains it must be considered in any 
discussion of this kind. The automobile is accused of 
many things in connection with street and road prob- 
lems; but it can at least be credited with this, that it 
is serving to wipe out the line of demarcation between 
the city and the country, so that the builder of good 
roads cannot longer feel that his work is done when he 
has worked out to the city limits. The time is com- 
ing when roadways will be considered very largely as a 
unit, irrespective of municipal boundaries ; but until 
that time they will have to be treated separately. 

Taking up first, then, the cost of city pavements, 
a few comparative figures will serve to show that con- 
crete is not high in first cost. We give cost data on 
these pavements in several different places in this vol- 
ume, but the large table of work done in 1912 will 
perhaps be sufficiently comprehensive for purposes of 
comparison, and they are more recent than many others 
given. 

In this table, which was compiled by The Cement 
Era, there are given cost figures for 81 cities; and 
while these figures were compiled from a number of 
different statements, representing, perhaps, widely 
divergent ideas as to what should be included in a cost 
statement, they are fairly representative, and it is of 
interest to note that they average a cost of $1.30 per 
square yard. Figaires compiled by Engineering and 



8 Concrete Roads and Pavements. 

Contracting for 141 cities ave practically the same, or 
$1.31 per square yard. While some of these statements 
include grading, many of them do not, as this is highly 
variable, the cost depending on the nature of the soil 
and the contour of the ground. They probably in most 
cases do not include also the item of engineering super- 
vision and administrative expenses. Some of the work 
was probably done, too, when cement was very low in 
price, so that a cost of $1.50 per square j^ard is perhaps 
as close a total average figure as can be given. 

And yet, taking all these things into considera- 
tion, the man who has had experience either in buying 
or building city pavements will know that this is as 
low a price as will buy any kind of a pavement accept- 
able to the general public. In fact, it is below the 
average price of any other material which any enter- 
prising city would think of using. 

It is interesting to compare the price of concrete 
pavement Avith the price of other classes of pavements 
as compiled by Engineering and Contracting in the same 
issue above referred to. In 272 cities reported as laying 
brick pavement, the average price was $1.82 ; the aver- 
age price for asphalt block in 14 cities was $2.48 ; for 
stone block in 46 cities, $2.96; for wood block in 44 
cities, $2.74, and for bitulithic pavements in 59 cities, 
$2.06. These figures are all for work laid in 1912. '^o 
figures are given for sheet asphalt, but a compilation 
made in 1911 for 20 cities shows an average price of 
$2.03. ]\rost of the figures given include a guarantee 
of from 1 to 6 years. 

These figures are als(^ exclusive of grading in a 
large number of castas and are also subject to an addi- 



Coucrcic ]\()(f(ls and Pfii'ciiirnls. D 

rioiial ehavii'o for overhead expense, as in the case of 
concrete. 

The sitnation reo-ardinc,- the use of concrete for 
country roads is entirely different. The first cost is 
naturally much higher than some of the forms of con- 
struction which have heen considered good enough in 
the past. Concrete cannot hope to compete with ordi- 
nary dirt or gravel roads in first cost ; but when its 
advantages of long life and low maintenance expense 
become fully established it Avill replace these, at least 
on most of the main highways of this country, and even 
on less important roads where the population and wealth 
are sufficient to make it possible. 

The eighth annual rejwrt of the Commissioner of 
Highways for the State of Maine, for the year 1912, 
contains a summary of the work done, in which is in- 
cluded six contracts on concrete roads totaling 21,128 
square yards and averaging $1.52 a square yard. This 
roadway all has bituminous top coating. This figure 
includes all expenses, such. as grading, manholes, drains, 
engineering and superintendence. Even at this, it is 
scarcely a representative figure, as it includes 1,000 
square yards at South Portland, which ran up to a price 
of $2.10 per square yard, owing to the fact that a large 
amount of rock base had to be put in. Leaving out this 
contract the five remaining contracts show a total of 
20,128 square yards put in complete at an average fig- 
ure of $1.1:0 per square yard. 

DuraJjility. While concrete has not been used as 
a road-making material long enough to determine its 
life in this use from actual experience, very fair in- 
ferences may be drawn from the general behavior of 
concrete under wear, as well as from the behavior of 



10 Concrete Roads and Pavements. 

such pavements as have been in use for a considerable 
length of time. In taking, account of this latter item, 
however, due allowance must be made for the fact that 
the first concrete roads, like the first concrete build- 
ings, were not constructed in accordance with present- 
day practice, and were far from reaching the degree 
of perfection which is now attained. 

There are two elements to be considered in deter-- 
mining the suitability of a material for a roadway — 
its wear under the elements and its resistance to traf- 
fic. That concrete can qualify under the first of these 
requires no argument. It has proven itself able to 
withstand any attack of atmospheric conditions, condi- 
tions of soil, fire, etc., at least as well as the best of 
natural stone, as is amply shown by the large num- 
ber of miscellaneous structures, under all kinds of 
conditions, which it has to its credit. 

While one may point for confirmation of his as- 
sertion of the durability of concrete roads to a large 
number of such roads which are standing up most 
successfully under traffic, perhaps one of the most con- 
clusive proofs of the value of concrete for this purpose 
is to be found in the comparative tests which have 
been made at Detroit with a device known as a paving 
determinator. This device was designed and built by 
Mr. John C. McCabe, boiler inspector of Detroit, for 
the Department of Public Works, with the idea of sub- 
jecting sample pavements to wear as closely approxi- 
mating actual conditions as possible. Eight sections of 
as many different kinds of pavement were first tested 
by this machine, a concrete section built under the 
Wayne County specifications giving by far the best 



Concrete Roach and Pacenients. 11 

wear. Full details of the tests made by this machine 
are given in Chapter XI. 

Comparing concrete and macadam pavements, Mr. 
Logan Waller Page, director of the Office of Public 
Roads, made the following statement before a meeting 
of the Association of American Portland Cement Manu- 
facturers in 1912 : 

'^In the matter of sustaining normal loads the ca- 
pacity of concrete pavements as compared with the 
capacity of ordinary macadam or bituminous macadam 
surfaces must be superior. J^umerical data or experi- 
mental evidence on this subject is as yet meager. It is 
not difficult, however, to draw^ certain definite conclu- 
sions when we consider the nature of the materials in- 
volved. It is well kno^^^l that macadam roads have 
rutted under heavy loads. For ruts to develop rapidly 
it is quite evident that some shearing of the macadam 
surface occurs. Of course, rutting also takes place^ 
because of wear and lateral displacement of stone. The 
capacity of concrete pavements to resist shear is rela- 
tively much greater, and we may perhaps note this as 
the first point of superiority of concrete over macadam 
pavements for sustaining normal loads. 

^^It is common practice to assume, in designing 
concrete bridge floors, that normal pressures over an 
area are transmitted through the slab in lines of pres- 
sure whose boundary surface is conical, with elements 
at an angle of 45 degrees or more with the horizontal. 
It scarcely needs demonstration that the same assump- 
tion cannot hold for macadam slabs, i. e., normal 
pressure cannot be transmitted by a macadam slab over 
as large an area of the sub-grade, and this, it is rea- 



12 Concrete Roads and Pavements. 

sonable to record, is a second advantage of concrete 
over macadam construction. 

^^A¥e may, if we choose, compare concrete road 
surfaces with macadam road surfaces, assuming that 
each is an arch between curbs. It is not difficult to sec 
that concrete is superior as an arch in the following 
Avav: Consider the entire sub-grade carefully re- 
moved from a macadam road surface; there is some 
doubt as to whether the macadam surface would stand 
alone. On the other hand it is easy to see the com- 
plete concrete slab crown not only standing after the 
removal of the sub-grade, but to also see this arch of 
concrete sustain considerable load without a sub-grade, 
so that we must admit the third superiority of concrete 
roads over any macadam construction in their action as 
an arch to sustain normal pressure. 

^Trom the comparisons made above between Port- 
land cement concrete and plain macadam or bituminous 
macadam, it is evident that we may be practically 
assured that the Portland cement concrete road is far 
better able to meet the changing traffic conditions than 
either of the other materials. From our knowledge of 
the strength of Portland cement concrete, we can de- 
sign a road surface of this material to meet practically 
any traffic requirement." 

Ease of Cteaning. The fact that Mr. Tillson as- 
signs to this item a value of 15 is conclusive proof 
that he has city pavements primarily in mind. Even 
under this high valuation, however, concrete pavements 
can qualify for a ]dacc equal to any. The fact that 
concrete is laid in large units is of itself perhaps a suf- 
ficient recommenchitiou on this point. This gives broad 
ex])anses of reasonably smootli surface to be cleaned. 



Concrete lloads (iiid Pdrenieiils. Vd 

free from freciTiciit joints, and the irregularities in sur- 
face which always n^snlt from tlie use of small units — 
surfaces easily cleaned Avith brooms or mechanical 
cleaners, or flushed with a hose. The only pavement 
to which it can be compared in this respect is sheet 
asphalt ; but this latter acquires so much unevenness 
of surface in the course of a few years, due to the un- 
equal bearing strength of the various parts of the sub- 
grade, that water does not readily flush it clean, and 
thorough cleaning with mechanical cleaners is almost 
out of the question. The concrete pavement, on the 
other hand, both by reason of the fact that it retains 
its true shape indefinitely, and because of the nature 
of its surface, is admirably adapted to the economy of 
mechanical cleaning. 

Col. George E. Waring, Jr., when street cleaning 
commissioner of Xew York City, made the statement 
that he could save the city $500,000 a year in the cost 
of cleaning if all the streets Avere paved Avith asphalt. 
Concrete paA^ement Avas not knoAvn at that time ; but 
Avith its advantage OA^er asphalt, as above pointed out, 
concrete could be expected to effect an cA^en greater 
saving. 

Resistance to Traffic. By this is meant the amount 
of friction dcA^eloped betAveen the pavement and mov- 
ing A'-ehicles, this factor gOA^erning the load AA'hich any 
giA^en power can haul over a road. As the amount of 
this friction varies Avith different materials, it stands 
to reason that the most economical roadway, other 
things being equal, is the one in Avhich this friction is 
least. 

Prof. Arthur H. Blanchard, of the Highway En- 
gineering Department of Columbia University, con- 



14 Concrete Roads and Pavements. 

siders sheet asphalt as the perfect pavement in point 
of ease of traction, assigning it a value of 10 on this 
point in making up the characteristics of an ideal pave- 
ment. To concrete he gives a value of 9, and to earth 
roads 2, other materials taking various intermediate 
values. He has given concrete a high place, to be sure, 
giving a better rating to only one other material; but 
we believe even this scarcely warranted. The elasticity 
and resiliency of asphalt do not make for ease of trac- 
tion, but rather the reverse; for an asphalt pavement, 
with its slightly yielding surface, is a nearer approach 
to a dirt road than an unyielding surface of concrete. 
Granting Prof. Blanchard to be correct, however, his- 
rating could only apply to a perfect asphalt surface, 
true to line in every direction, which is something sel- 
dom to be found, and which the pavement rapidly de- 
parts from, even if conforming to it when first laid. 
On the other hand, as already pointed out, concrete 
holds its original shape, subject only to slight and 
usually uniform wear. 

Taking it in another way, it may be stated that to 
move a weight of one ton will require a tractive force 
of 100 pounds on a dirt road, 40 pounds on macadam, 
25 pounds on brick pavement and 20 pounds on con- 
crete; in other words, that a horse on a concrete road- 
way can draw five times as much as on a dirt road and 
twice as much as on macadam. 

Non-Slipperiness. This is a factor which is more 
tmder the control of the builder in concrete than in 
any other material, it being possible to make the sur- 
face of almost any desired texture. 

Ease of Maintenance. While we continue to fol- 
low Mr. Tillson's headings, this might perhaps better 



Concrete Roads and Pavements. 15 

have been ''Cost of Maintenance/' although each term 
may by inference be made to include the other. It is 
the cost of maintenance, however, which goes into the 
records of a municipality, and by which the success or 
failure of a pavement will very largely be judged as 
the years go by. On this point alone concrete is des- 
tined to win a vast number of friends as its low main- 
tenance cost becomes generally known. 

Consider for a moment this question : What is the 
maintenance cost of a well-laid basement floor or a 
properly constructed concrete sidewalk ? True, some 
floors will require an occasional patch and some walks 
an occasional square replaced; but equalize these 
charges over the total life of the structure and it will 
be found that the annual charge is very small indeed. 
So it is with a concrete roadway — the first cost is prac- 
tically the only cost, requiring ridiculously small ap- 
propriations for maintenance, and allowing municipal- 
ities and road districts to spend most of their money 
on new" construction. 

The oldest concrete pavement of which the writer 
has knowledge was built at Belief ontaine, Ohio, in 1893 
and 1894. This pavement contains 4,400 square yards 
and was built in two courses. On December 14, 1912, 
Mr. C. A. Inskeep, city engineer, stated that the ap- 
proximate total cost for repairs had been $200. 

When laid the pavement was cut into squares, sim- 
ilar to those commonly seen in cement concrete side- 
walks, and the principal part of the wear has been 
along the longitudinal joints thus formed. The wheels 
of vehicles form grooves at these places which they have 
a tendency to follow. 

Eepairs have usually been made with cement mor- 



IG Concrete Roads and Pavements. 

tar or concrete, which has been placed in the grooves 
after they have been chiseled ont. Sometimes this patch 
has been dovetailed in; that is, the sides of the notch 
incline towards the axis of the groove rather than out- 
wards. 

In some places paving bricks, laid crosswise, have 
been cemented into the prepared notch instead of mak- 
ing the entire patch of concrete. This has. been done 
when it was impracticable to keep traffic off the street 
long enough for a concrete patch to harden. 

If the reported figures are accurate, the total re- 
pair cost has been only 4. 77 cents per square yard in 
.18 years, or 0.265 cent per square yard per year. 

In their report for the year ending September 30, 
1912, the highway commissioners of Wayne County, 
Mich., state: ^^The only surface repair required on 
our concrete roads has been the refilling of the con- 
traction joints with tar and sand on the roads first con- 
structed, where the joints were not protected with armor 
plates. The cost of refilling these joints did not add 
to exceed $100 all told to our maintenance costs." 

The maintenance cost of an asphalt pavement runs 
from 5 to 35 cents per yard each year, depending on 
the quality of the first installation and the state of 
repair demanded by the city. In some thickly popu- 
lated districts the maintenance of a macadam pavement 
has been known to cost as much as the original con- 
struction, meaning a practical rebuilding each year. 

Figures collected by the Office of Public Koads 
relative to the cost of maintenance of plain macadam 
and bituminous macadam pavements under fairly heavy 
traffic conditions indicate that these pavements, when 



Concrete Boads and Pavements. IT 

properly maintained, entail an annual absolute main- 
tenance charge of approximately $450 per mile per 
annum for plain macadam, and possibly from $800 
to $1,000 per mile per annum for bituminous macadam, 
for 15-foot surfaces. These figures have led Mr. Logan 
^Valler Page, director of the Office of Public Roads, 
to believe that we must seek a more permanent form of 
pavements for country road surfaces. 

Favorahleness to Travel. By this is meant the 
ease and comfort of riding, as well as the reduction of 
wear and tear on vehicles to a minimum. The fact 
that concrete is placed in large and unyielding sections 
is perhaps a sufficient argument for it in this regard. 
There is not the frequent recurrence of joints found in 
many other tyjDcs of pavement, tending to wear the 
vehicle and reduce the comfort of passengers, even 
when such a pavement is at its best; while the dete- 
rioration of many small units, the rounding of the 
edges and the gradual settling in spots as traffic pro- 
gresses, produce an increasing unevenness and corre- 
sponding discomfort. A concrete pavement not only 
presents a broad expanse of unbroken surface, as has 
been spoken of before, but it has within itself sufficient 
strength to bridge over weak spots in the sub-grade. 

In October, 1911, Mayor Gaynor of 'New York 
appointed a special committee on pavements, to investi- 
gate and report to him on the condition of the pave- 
ments of that city. In making its report this commit- 
tee said : 

''JSTo quality which a pavement can possess is more 
important than smoothness. Every irregularity in the 
surface is a source of weakness and of ultimate failure. 
As the wheels are drawn over the road, the wear which 



18 Concrete Roads and Pavements. 

they cause is almost in proportion to the obstacles en- 
countered. If the pavement is rough, as our stone ones 
are, or if it be broken, the wheels pound, and the pave- 
ment is subjected to heavy blows Avhich soon wear it 
away and otherwise destroy it. In almost all our stone 
pavements one can find places where the blocks have 
actually been crushed or split from this cause.^ If the 
pavement is of wood block, asphalt or any other com- 
position material, and the surface is wavy, the depres- 
sions will hold water and speedily lead to failure; in 
such pavements disintegration almost invariably com- 
mences in these places. In luacadam roads, depres- 
sions of this sort are the chief cause of wear, and 
especially so since the introduction of the automobile. 
The rapidly passing wheels throw out the standing 
water with great violence, carrying with it the binder 
or fine stuft' between the stones, thus causing the pot 
holes Avhich make their appearance so rapidly on sucli 
roads when subjected to heavy automobile traffic. 

''It should be remembered that since the advent 
of the automobile, smoothness for pavements is an even 
more important quality than it was formerly. The 
shock which a swiftly moving vehicle receives when it 
meets an obstruction, is more violent and destructive in 
its effects than if it were proceeding at a more moderate 
gait, and no matter how the force of the blow may be 
disguised from those riding in the car, by springs, pneu- 
matic tubes or otherwise, the destructive effect of the 
blow remains the same and is absorbed by some part 
of the mechanism, causing injury either to the tires 
or frame. 

''The loss sustained yearly by the citizens who 



Concrete Roads and Pavements. 19 

use automobiles, by reason of the roughness of our 
pavements, must be very great in the aggregate.'' 

Sanitariness. On this last point it will readily 
be conceded that concrete has no equal as a road and 
pavement material. It contains in itself nothing vrhich 
can decompose or become objectionable ; it offers neither 
a porous surface nor numerous joints for the collection 
of street refuse, where it can decay and become a menace 
to public health. Any liquid refuse which might pene- 
trate the surface of a concrete pavement, which will 
be smaller in amount than on any other class of pave- 
ment with the possible exception of sheet asphalt, will, 
to a large extent, be neutralized and made harmless by 
the lime in the concrete. 



CHAPTEE II. 

The Construction of Concrete Roadways. 

While practice in the construction of . roads and 
pavements will differ in different localities, because of 
A^arying materials, equipment, and other conditions, thi.^ 
writer feels that he can do no better than to recommend 
a close study of the specifications of the ^N'ational As- 
sociation of Cement Users in Appendix A, or the 
A7ayne County Specifications, in Appendix B. 

There are, as is perhaps generally well known, two 
general types of concrete pavement, designated by the 
terms One Course and Tiuo Course. The former of 
these is laid of one mix of concrete throughout, and 
])laced in one ojDcration; while the latter has a base of a 
lean mix with a wearing surface richer in cement, and 
usually with a harder and more wear-resisting aggre- 
gate. 

While- it may be said that the one-course roadway 
seems to be growing in favor, the determination of the 
type to be employed must be governed largely by local 
conditions. If, for instance, the aggregate most readily 
available is of a soft nature and readily crumbles under 
abrasion, a better and more economical pavement will 
be secured by using this in a base course, with a wear- 
ing surface in which granite or some other hard rock 
is used as an aggregate. This small amount of granite 
will take the wear of traffic, while the bottom course 
with the local aggregate will have sufficient strength 
foi' a foundation. Some cities which are putting in 

(20) 



Concrete Boads and Pavements. 21 

large aiiioimts of coiicrett' paving, such as Mason City, 
Iowa, find it advantageons to follow this method. In 
other localities, where there are available deposits of 
hard gravel, or other stone suitable for this work, which 
does not have a sufficient market value to make its use 
extravagant, a one-course roadway can be laid to good 
advantage. While this type requires slightly mow 
cement per yard, the labor cost is less ; in localities 
where cement is high in price, however, these two items 
will have to be balanced against each other, though it 
^vill probably be found that any difference will be in 
favor of the one-course type in almost every case. This 
type, also, leaves no possibility for the separation of 
the wearing surface from the base, as may happen in 
a two-course pavement if sufficient care is not exercised 
in laying. 

Suh-Grade. The sub-grade may be either flat or 
curved to the crown of the finished road. While there 
may be certain advantages of construction in this latter 
method, and while it is perhaps more frequently fol- 
lowed than the other, it is the belief of some of the best 
road builders that a better roadway can be built on a 
flat sub-grade. Their position is, it would seem, well 
taken. It is at once apparent that this will give greater 
thickness, and consequently greater strength, in the 
njiddle of the pavement, where greater strength is 
needed. A plotting of all the strains on the pavement 
will show this design to have additional advantages. A 
flat sub-grade also facilitates the ^^crawling" of the 
pavement due to expansion and contraction, and thus 
lessons the tendency to crack. 

For this latter reason, too, the sub-grade should be 
smooth, free from humps or depressions. Soft and 



22 Concrete Roads and Pavements. 

spongy places must be removed and filled in with the 
same material as the body of the road. The sub-base 
must be kept wet while being compacted, and also should 
be thoroughly wet when the concrete is deposited, in 
order that the water in the concrete may not run away. 

If the subsoil is of a character to retain water, it 
is very important that such a system of underdrainage 
be installed as will carry the underground water from 
beneath the road. In the dry summer weather this 
work may not appear necessary, but information should 
always be obtained regarding the action of the subsoil 
during the wet season and when frost is coming out of 
the ground. 

There are, of course, many soils of a gravelly, 
sandy, or other character which are self-draining and do 
not require particular attention, but it is a fact that the 
defects in most of our country highways which are built 
upon clay soils or those which do not drain themselves, 
are to be attributed to a lack of drainage. There are 
two general methods in use to dispose of the water. One 
is to lay a 3- or 4-inch land tile under the shoulder and 
about 12 inches outside the edge of the concrete. The 
ends of the tile should be placed close together and 
clean stone of at least 1%-inch size put on the sides 
and top of the tile to a depth of 3 or more inches. If 
there is any danger of dirt reaching and getting through 
the joints, the upper half of the tile at the joints should 
be covered with paper before the stone is put upon it. 

The other method is to lay a French drain in the 
same position. With this type of drain the best results 
are obtained by placing in the bottom flat stones of 6, 8 
and 10-inch dimensions. Those should be laid in the 
form of a culvert and should be covered to a depth of 



Concrete Boads and Pareiiwnts. 25 

about 6 inches with smaller stone of not less than IV2- 
inch size. The width of the ditch should be about 12 
inches. In both cases the depth of the bottom depends 
upon the character of the subsoil, but should in no case 
be less than 18 inches below the finished grade of the 
road at the crown. 

Materials. In order to j)i*o<^^T^^ce the most satis- 
factory roadway, the aggregate for the wearing surface 
should be ^^sufficiently hard to scratch glass." Natural 
mixed aggregates as they come from the deposits should 
not be used. It has been found to conserve both 
economy and durability to properly grade the ma- 
terials. Suggestions for the proportions of materials 
of the various sizes will be found in some of the speci- 
fications ; but this, too, has to be governed somewhat by 
local conditions, and on work of any extent it will be 
worth while for the engineer to make a careful study of 
the materials and work out a formula for use on that 
particular job. 

The materials must be clean, free from loam or 
organic matter, as these will, if they should come at or 
near the surface, inevitably result in holes. 

Proportions. The Wayne County mix for one- 
course roadway of l:lV2:o is perhaps the last word on 
this subject, as it has been arrived at after a great deal 
of study and experiment. It is practically the same as 
the specifications of the ^N'ational Association of Cement 
Users, which recommends ^^not more than 2 parts of 
fine aggregate." The Wayne County mix is not only 
giving remarkable results in actual practice, but has 
passed surprising tests, as detailed in another chapter. 
^Xot all roads, however, will be called upon to endure 
the same heavv traffic as those of Wavne countv, and in 



24 Concrete Roads and Pavements. 

many localities a 1 :2 :4: mix will very likely build a 
road which will meet all requirements. 

For a two-course pavement the best practice re- 
quires a base of 1:2% :5j or 1:2:5, with a 1 :2 wearing- 
surface. 

Consistency. For a one-course pavement the con- 
crete may preferably be mixed so wet that it will flow 
into place with only slight spading. The base of a 
two-course pavement cannot be quite as wet as this, 
but will usually require light tamping before the top 
surface is put on. 

Methods of C onstruction. Aside from a good con- 
crete mixer, preferably of a type which can be moved 
readily along the work and deliver directly onto the 
sub-grade, very little equipment is required. 

Two-inch plank, the width equal to the thickness 
of the roadway, are placed on the sides of the prepared 
sub-grade and securely staked in position, the stakes 
being driven a little below the edge of the plank so as 
not to interfere with the movement of the template by 
which the surface is finished. Care must be taken that 
the planks fit close to the ground, so that the water in 
the concrete cannot run away under them. 

The mixer and the side forms are the basis of 
equipment. Various other things may be used at differ- 
ent times, such as carts for hauling the materials to the 
point of deposit, but it must be borne in mind that the 
more nearly the materials can be distributed along the 
roadway in the quantities needed, and the more often 
the concrete can be delivered direct, the more rapid 
will be the ])rogress and the lower the unit cost. 

A good ])1an of organization for carrying on con- 
crete road Avork, and based on practice in Illinois, is 



Concrete Roads and Pavements. 25 

to divide the work in two parts, each under a competent 
foreman or superintendent. The first party will do the 
grading, prepare the sub-grade carefully and haul the 
aggregate on the roadbed in such quantities that there 
Avill be sufficient to provide for the concrete. It is bet- 
ter, however, to have slightly less than too much aggre- 
gate in the roadway, as it is more economical to haul 
in an extra load or two to make up any deficiency tha! 
may occur than to dispose of a surplus. 

It should be borne in mind for estimates for this 
part of the work that there will inevitably be a small 
amount of aggregate left on the roadbed, which is by 
no means a bad feature, so that there should be allowed 
a full cubic vard of gravel or stone for each cubic vard 
of concrete to be laid. 

The second j^arty comes upon the work with the 
concrete mixer and starts in at one end of the road to 
mix and j)l^ce the concrete. With an automatic dis- 
tributing type of machine, five to seven men will be 
about all that can be used advantageously in shoveling 
the material into the hopper. Two men will be required 
on the machine, one man to clean up as the machine ad- 
vances, so that the concrete may be placed on a clean 
roadbed ; two or three men taking up the forms as used 
and putting them ahead ; three men to strike the work, 
using the template, and two finishing with floats. Par- 
ties so made up, with a 12 -foot capacity mixer, will lay 
from 500 to 800 square yards of T-inch concrete a day 
of ten hours. The teams necessary for this part of the 
work would be only those required to haul the cement 
and an occasional load of gravel as deficiency may be 
experienced. 

There are sections of the country Avhere continued 



20 Concrete Roads and Pavements. 

siiltrj Slimmer weather prevails when it will be neces- 
sary to work the shovelers in two gangs, working from 
15 to 20 minutes each. Either this must be done or the 
progress of the whole party reduced to about one-half 
what it is in cooler weather. 

A third party might be organized to trim* the 
shoulders and attend to final finishing of the sides and 
ditches. 

Surface Finish. The surface of a road should not 
be finished smooth, but left slightly rough. This may 
be done by the workmen using a wood float, or it may 
be done after the work has been floated fairly smooth 
by slightly marking the surface with a broom. This 
latter method is perhaps better adapted to rock and 
sand concrete than gravel concrete, as the latter will 
leave many small pebbles in the surface and not finish 
Avith so smooth a mortar surface as sand and rock con- 
crete. Brooming should be done from side to side of 
the roadway rather than lengthwise. 

On city pavements a smooth finish is sometimes 
desired, though even here a rough finish would seem 
to be preferable. 

Where a street or road is on a grade of more than 
4 per cent, the concrete should be marked off with 
transverse grooves to prevent slipping. 

When a concrete roadway is to be supplemented 
with gravel shoulders, the edge of the concrete is usually 
trimmed off slightly when the side rails are removed, so 
as to prevent an abrupt line between the concrete and 
gravel. 

Expansion Joints. These are treated separately 
in another chapter. 

Protection. Even if a good mixture has been used, 



Concrete Boacls and Pacenients. 27 

a bad pavement may result if proper care is not taken to 
supply an abundance of moisture while the cement 
hardens. Shrinkage cracks occur if the concrete has 
not been covered and kept thoroughly moist, for a 
period of not less than two weeks. A good method 
to secure proper curing is first to cover the concrete 
with canvas as soon as it has taken an initial set so that 
it will not be marred. The canvas is kept moist, and 
then in a few hours, or as soon as the road becomes set, 
sand or earth is shoveled upon it and kept wet. 

Mr. A. X. Johnson, engineer of the Illinois State 
Highway Commission, calls attention to the fact that 
each batch of concrete as deposited in the road should 
be watched, that the mortar does not flow to the edge of 
the pile and leave a core of aggregate unsupplied with 
sufficient mortar. At least one workman should be as- 
signed to shovel all such cores of aggregate to the bottom 
of the concrete layer so as to insure only cement rich 
in mortar at the surface. If this is not done, depres- 
sions will develop in the surface under traffic which will 
loosen the clusters of pebbles of the aggregate which do 
not have sufficient mortar to hold them fairly in place. 
The men finishing the surface should be warned not to 
let such places go by them without shoveling out the 
pebble clusters and replacing them with a richer mix- 
ture. A finisher can easily cover such a place by work- 
ing a film of mortar on the surface without necessarily 
filling the voids below. 

Use of the Template. The template should be 
]nade of wood, very rigid, and cut to the crown of the 
road, and should have two handles on each end so as to 
make easier its operation. A man at each end works 
it back and forth and at the same time moves it slightly 



28 Concrete Roads and Pavements. 

forward. This side motion requires that the template 
be about tAvo feet longer than the width of the road. 
When there is an excess of material, it is necessary to 
use the template as a scraper — getting the approximate 
shape — and go over this section again with the back- 
and-forth motion. By the use of a sloppy wet mixture 
the template worked in this manner gives the concrete 
sufficient tamping and brings to the top sufficient mortar, 
to produce an even surface. If, however, the stone used 
in the concrete is too large — over 1^/4 inches — the tem- 
plate will drag the large pieces along and leave holes 
behind the template. 

In moving the template forward, it is pointed out 
by Mr. W. A. Mclntyre of the Association of Portland 
Cement Manufacturers, that some of the larger stones 
are pidled from the surface and collect in front of the 
template, making the operation hard to perform, expos- 
ing a lot of uncoated stone, and causing water carrying 
cement to run off the sides. The stones should be 
scraped forward by a man with a shovel, and deposited 
in the bottom of the concrete layer. In running the 
template over the surface a second time, rich mortar 
collects as did the stone the first time, and has a ten- 
dency to run off at the sides. This should be scraped 
forward the same as the stone. 

Care should be taken in moving the template for- 
ward that it is not lifted from the side forms and moved 
two or three inches at a time. Such an operation will 
leave the surface full of little undulations and make 
the road noisy and uncomfortable for travel. 

After the template lias been used the surface of 
the concrete is left quite wet and in a condition which 
will not give good results if troweled at once. 



Concrete Roads and Pavements. 29 

Sufficient time should elapse in order that the ex- 
cess moisture will be absorbed or evaporated and then 
the surface should be troweled with a wooden float 
wherever necessary. The time between using the tem- 
l^late and floating depends upon the condition of the 
weather, but is usually about thirty or forty minutes. 
Care should be taken not to overtrowel and thus bring- 
to the surface too much fine stuff. 

Troweling should be done from a bridge spanning 
the road and resting upon the side forms. Then there 
is no danger of the wet concrete being disturbed by 
placing planks upon it or by the finishers trying to take 
in too large an area without moving and stepping upon 
the surface. Such a bridge is cheap and has the added 
advantage of allowing the workmen a short cut from 
one side of the road to the other. 

Comparison of Hand and Machine ^Yorh. Mr. C. 
II. Hubbell, of Davenport, Iowa, made some interest- 
ing comparisons on work done in 1911 and 1912, hand 
mixing being used in one year and machine mixing the 
other. ]\Ir. Hubbell reported his findings in an article 
in Municipal Engineering, summarizing the work as 

follows : 

Hand Machine 
Mixing Mixing 
cii. yds. cu. yds. 
Average yardage per man on street pavement 

(except watchman, water and sack boys) 2.31 3.83 

Average yardage per man on street pavement 
(including all engaged in the mixing 

operation) 3.04 4.788 

Cost per cu. yd. of street pavement (includ- 
ing only wheelers, loaders, mixers and 

spreaders) $0.64 $0,508 

Cost per cu. yd. of street pavement (includ- 
ing all engaged in the mixing operation). 1.075 0.74 

The machine used was a Xo. l-t Koehring special 



;]0 



Concrete Roads and Pavements. 



paving mixer, whicli gave an average yardage of 200 
per day with the following gang : 

In Front of Machine: 
3 stone wheelers, 

8 stone loaders (two loaders per barrow), 
3 sand wheelers and loaders (two barrows), 

1 cement wheeler (three sacks per load), 

3 machine men (fireman, engineer, bucket man). 

At Rear of Machine: 

2 spreaders, 
1 tamper, 

1 template setter and block placer, 

2 finishers. 

The following calculations show the detailed labor 
costs of job Aj as Avell as summaries of the unit costs 
of jobs A, B, C, and J), of the work above referred to: 



Job A, 3,100 Sq. Yds. 

Base 5 in. 1:3:5. 

Average output equals 530 sq. yds. 

Time 5.7 hrs. 

Total 

9 men on rock at 22i^c $11. 5o 

3 men on sand at 22 ^/^c 3.85 

1 man at skip at 22V^c 1.28 

1 man wheeling cement at 22 ^c 1.28 

1 man leveling concrete at 25c 1.43 

1 helper leveling concrete at 22V^c 1.28 

1 tamper at 22i^c 1.28 

1 engineer at 25c 1.43 

1 fireman at 25c 1.43 

1 bucket operator at 15c 0.86 

1 water boy at 05c .28 

1 foreman at 45c 2.57 

Total $28.80 

Wearing surface, 1^2. in. 1:1:1. 
Average output, 530 sq. yds. 
Time, 2.8 hrs. 

Total 

4 men on granite chips at22i/^c $ 2.52 

4 men on sand at 22i/^c 2.52 

2 men on skip at 22i^c 1.26 



Per 
sq. yd, 
$0.0218 
0.0073 
0.0024 
0.0024 
0.0027 
0.0024 
0.0024 
0.0027 
0.0027 
0.0016 
0.0005 
0.0048 

$0.0543 



Per 

sq. yd. 

$0.0048 

0.0048 

0.0024 



Concrete Roads and Pavements. 31 



2 men wheeling cement at 22V2C 1.26 0.0024 

2 rough spreaders at 221/20 1.26 0.0024 

1 fine spreader (also tamps top) at 25c 0.70 0.0013 

1 fireman at 25c 0.70 0.0013 

1 engineer at 25c 0.70 0.0013 

1 bucket operator at 15c 0.42 0.0008 

1 water boy at 05c 0.14 0.0002 

1 sack boy at 05c 0.14 0.0002 

1 foreman at 45c 1.26 0.0024 

Total $12.88 $0.0245 

Finishing (530 sq. yds.) 

1 finisher, 13 hrs at 25c $3.25 $0.0061 

1 helper, 13 hrs at 22y2C 2.93 0.0055 

Total $6.18 $0.0116 

Form Setter. 

1 man, 10 hrs. . at22y2C $2.25 $0.0042 

Miscellaneous. 

1 man trimming grade, 10 hrs $2.25 $0.0043 

2 men cleaning up stone, sand, etc., while 

top is being placed, 4.3 hrs. each 1.49 0.0036 

Total $4.19 $0.0079 

The time required for moving the machine was 
15 hours for 8 moves. The wearing surface organiza- 
tion is charged with moving the machine ; so to arrive 
at cost take 1.5/2.8x$12.S8, which equals $6.00. 

Unit cost equals 0.013 per square yard. 

Summary, Job. A. 

Per Per 

sq. yd. cu. yd. 

Development expenses $0.0090 $0.0500 

Watchman 0.0050 0.0277 

Base 0.0543 0.3008 

Top 0.0245 0.1357 

Finishing 0.0116 0.0643 

Setting Forms 0.0042 0.0233 

Miscellaneous 0.0079 0.0438 

Cleaning street, boulevard, etc 0.0055 0.0305 

Moving machine 0.0130 0.0730 

Total $0.1350 $0.7481 



o"2 Concrete Roads and Pavements. 

Summary, Job B (2,300 Sq. Yds.) 

Per sq. yd. 

Development expenses , $0.0088 

Watchman 0.0048 

Base 0.0526 

Top 0.0237 

Finishing 0.0112 

Form setting 0.0041 

Miscellaneous 0.0071 

Cleaning street, boulevard, etc 0.0054 

Moving machine 0.0125 

Total $0.1302 . 

Laborers' wages were 22 1^ cents per hour, and condi- 
tions were almost identical with those of Job A. 

Summary, Job C (3,500 Sq. Yds.) 

Per sq. yd. 

Development expenses $0.0185 

Watchman 0.0060 

Base 0.0595 

Top 0.0268 

Finishing 0.0122 

Form setting 0.0047 

Miscellaneous 0.0080 

Cleaning street, etc 0.0061 

Moving machine 0.0141 



Total $0.1514 

Laborers were paid 25 cents per hour on this job. De- 
lays were frequent, due to shortage of rock, sand and men. 

Summary, Job D (1,600 Sq. Yds.) 

Per sq. yd. 

Development expenses $0.0155 

Watchman 0.0060 

Base 0.0584 

Top 0.0260 

Finishing 0.0120 

Form setting 0.0042 

Miscellaneous 0.0080 

Cleaning street 0.0041 

Moving machine 0.0130 

Total , $0.1472 



I 



quoting extensively from these addresses. 

(33) 



or contraction, as I believe 
aterprooflng the surface in our climate 
ovides for same. The alley in question 
Tries a heavy teaming traffic and so far 
ows no evidence of deterioration. The 
St under private contract was 13 cents 
r square foot, with gravel at $1.10, sand 
e same, and cement $2.50 a barrel. Labor 
.00, teams $4 to 5, oil 90c barrel (42 gal.), 
nuch prefer crushed rock and screenings 
same properly proportioned, not exceed- 
; 1 inch in largest size of aggregate, and 
mt machine mixed concrete with power 
raying in two or three light coats of not 
ceeding % gallon to yard, all told. In 
is particular instance the rock was too 
arse (Max. 3 inches) for a floor of 4 
ches, though power mixed, and the oil was 
iplied in one coat by gravity, and in too 
eat quantity, showing a tendency to run 
center. Generally speaking, I am in 
vor of flat crowns for asphalt or concrete 
ads, conditioned upon ample longitudinal 
11, as conducing to more uniform use of 
itire width of street. We had nearly 3 
iles of various forms of asphalt last year, 
informing generally to a 6-inch crown for 
width of 46-foot roadway, and experience 
IS demonstrated that the traffic does not 
inter, but is uniform over the entire width 
: roadway, thereby conducing to the life 
' pavement. Pomona lies upon a plane of 
om 1 to 2% per cent grade, and most of 



however slight, for the effect if nothing else. 
For a width of 46 feet six stakes are ample 
for section and 10 feet to 16 feet longi- 
tudinally, as required by the character of 
the work and in forming an intersection of 
streets as many as 60 or 70 stakes are re- 
quired." 

Highland Park, 111.— Jas. Shields, city en- 
gineer, like many of the other engineers, 
takes occasion to state that their pavement 
is in flrst-class shape. He states also that 
the price of $1.01 includes materials, labor, 
etc., but not engineering inspection and 
superintendence. A tile drain was placed 
3% feet below the street grade under each 
curb and back filled with cinders to keep 
water from under paving. He says that the 
citizens are very much pleased with the 
paving. 

Richmond, Ind. — Fred R. Charles, city en- 
gineer, supplements his report with this 
statement: "In paving between car tracks 
the ties are bedded in concrete the usual 
way, and the foundation connects up to the 
top of ties; when fully set, the surface is 
sprinkled with sand to form a joint of sepa- 
ration, and concrete made 1-3 proportions, is 
filled in to top of rails, and stuck off with 
a template cut the proper shape to give the 
groove for the wheels along the rails. Sur- 
face of concrete is finished by floating rough. 

Marshalltown, Iowa. — W. H. Stein, city 



a considerable amount of concrete pave- 
ment in previous years, beginning with 1907, 
and Mr. Brian Bradbury, .Jr., commissioner 
public works, says that it is wearing well 
and there has been no cause as yet for main- 
tenance 

Alpena, Mich. — This city built some con- 
crete pavements in 1909 and 1910, and Jos. 
W. MacNeil, city engineer, says that it is 
all in good shape. 

Ann Arbor, Mich. — This city has done a 
considerable amount of paving, beginning 
with 1909, and Manley Osgood says that it 
is wearing, very well where laid in two 
courses. He adds that the citizens like it 
very much. 

Minneapolis, Minn. — This city has tried 
concrete paving for the first time, and likes 
it so well that it will do further work of 
the same kind. The price given in the table 
is based on gravel at $2 per yard on the 
job, cement at 86% cents on the car, sand 
at 75 cents on the job, and labor at $2.40 
per eight-hour day. 

Kansas City, Mo. — Mr. Clark R. Mandigo, 
assistant city engineer, states: "There were 
52 public contracts let tor paving streets 
with concrete, aggregating 12.1 miles, or 
198,443 square yards. This pavement called 
for a total cost of $211,148. This includes 
sub-grading, a five-year guarantee, and pay- 
ment in tax bills against the abutting prop- 



yards. This was laid at an average cost of 
$1.10 per square yard, under the same speci- 
fications and conditions that the street pav- 
ing was laid. In addition to the public con- 
tract work, 2.8 miles of concrete pavement, 
or 38,500 square yards, was laid by private 
contract, under the supervision of the en- 
gineering department. It will, therefore, be 
seen that Kansas City put down over 250,000 
square yards of concrete pavement during 
1912 — probably more than any other city in 
the United States." 

Trenton, N. J. — Harry F. Harris, assistant 
engineer of streets, reports work done in 
1911 wearing very good. The prices given 
include excavation, material and labor. He 
stated that after experimenting with both 
types of construction, his city is inclined to 
favor one-course method, using wet mixture 
of about 1-2-4 or l-iy2-3. 

Sheboygan, Wis.— C. U. Boley, city en- 
gineer, states that work done in 1911 does 
not show wear except a slight smoothness 
of the surface. The price given for rein- 
forced concrete pavement includes every- 
thing except engineering inspection. 

Aberdeen, Wash. — Chas. W. Ewert, city 
engineer, says that the work done in 1910 
and 1911 is wearing in first-class shape, 
showing only a few hair-line contraction 
cracks. The work is given a brush finish. 
Price as given includes material and labor. 
For engineering he adds 2.9 per cent. 



DATA ON CONCRETE PAVEMENTS LAID IN MANY CITIES IN 1912. 






Connecticut- 
Sauth Noi 



Two Course Work 

-Base. Top. Day Labor 

Aggregate Used. Expansion Joints Soil or Cost Per Remarks Sq. Yds. So. Yds. 

Contract Yd. Mixer Previous To Be Done 



Thick, por- Tliic 



F Cotunib 



Highlan. 



Ft. Waj 
H-ndngto,, 






49,800 



Shreveport 10,600 






.... '■•' uolarway surtace 



Maine— 



«SS 



HisLland Park... 12.500 24 5 1-3.5 2 1.2S4 Trap rock in wearing 3o"f'':Vter7oi„ts. Clay 

Kalamazoo 206 42 5 1-0 2 1-2 CrS'.T' stone and S6 ft. both directions Grave 






Ne^"v'i",r 



Norwal 



Sheboygan" 2r>.tJO0 



.eX„"- 



Dolarway surface 



CHAPTER III. 
The Koads of Wayxe Couxty, Michigan. 



The concrete roads of Wavne County, Michigan — 
the county in which Detroit is located — haye become 
deservedly famous and are inspected almost daily by 
parties of road builders from other parts of the country. 

There are at least two good reasons why these 
roads are worthy of special consideration. In the first 
place, the people who haye built them approached the 
subject of roadmaking with open minds, intent only on 
getting a road which would best stand the traffic, and 
without a predisposition to fayor any one material above 
another; the final adoption of concrete means, there- 
fore, that this material proved itself to be, in their best 
judginent, ahead of any other.. In the second place, 
once having adopted concrete, they exercised the same 
openmindedness regarding their methods of construc- 
tion, revising their specifications and practice from year 
to year as their experience has shown this to be desir- 
able. Their present specifications, as given in Ap- 
pendix B, probably represent, therefore, the very best 
practice now in use anywhere. 

Mr. Edward X. Hines, a member of the board of 
road commissioners of Wayne County, has devoted a 
large amount of time to the development of the concrete 
road, and has told in a large number of public ad- 
dresses throughout the country what Wayne County is 
doing. A good idea of this work can be gained by 
quoting extensively from these addresses. 

(33) 



34 



Concrete Uoads and Pavements. 



^The experience of the Wayne County Road Com- 
mission is particularly valuable because we were not 
committed to concrete at the outset/' said Mr. Hines 
before the Association of American Portland Cement 
Manufacturers in May, 1912. ^^Detroit is the heart of 
the automobile world, and the number of automobiles 
owned per capita is comparatively very high. This 




A W^ayne County Road Before Improvement. 

new vehicle quickly demonstrated here, as elsewhere, 
the purely temporary character of many so-called good 
roads. The automobile picked up the good roads in fine 
particles and scattered them over the countryside. The 
modern demands upon highways necessitated new 
methods and new materials, and we used concrete to 
meet these demands. 



Concrete Roads and Pavements. 



35 



''The Commission, when first organized, followed 
the accepted practice and started in to build bitumi- 
nous macadam roads; but after a year's experience in 
noting the wear upon them, foreseeing a constantly in- 
creasing maintenance charge, and harking to the world- 
wide cry, 'What shall we do to save our macadam roads 
from the ravages of the automobile?' decided that a 
change was not only desirable, but necessary, and we set 
out to find a more permanent and durable material 
which would approximate in initial cost that of a first- 
class macadam. 

''After thoroughly investigating the subject, study- 
ing the experience of near-by smaller towns in the mat- 
ter of concrete crosswalks, inspecting concrete bridge 
floors, and noting the general satisfaction concrete was 
giving in other forms of construction, the grades of 




Finishing with W^ood Floats. 



36 Concrete Roads and Pavements. 

material used, the light form of construction as applied 
to cross-walks and bridge floors, we decided that a con- 
crete road would come more nearly realizing the ideal 
than other forms. The points considered as being in 
its favor were : Comparatively low first cost ; low main- 
tenance cost; freedom from dirt (there being no detri- 
tus from a concrete road in itself) ; its comparative 
noiselessness ; ease of traction for vehicles of all de- 
scriptions, and the small crown necessary to get rid of 
surface water. While we were reasonably sure of our 
ground, we also felt that in case we scored a partial 
failure we could use the concrete for foundation pur- 
poses. 

^'Three stretches of road, aggregating two miles, on 
varying subsoils and with differing specifications, were 
decided upon. 

^'These roads are starting on their fourth year of 
wear, and barring some longitudinal cracks are as good 
as the day they were built, and practically nothing has 
been spent on their surface for maintenance. On the 
basis of three years' thorough trial, I stand committed 
to the use of concrete for country roads. I also believe 
concrete to be an ideal form of paving for village and 
city residence streets and alleys. This is not a state- 
ment born of enthusiasm on the spur of the moment, but 
a cold-blooded dollars and cents view, based on results 
attained and arrived at after careful consideration of 
all the facts available and experiences imdergone. 

'Tt is to be expected that on our first experimental 
work we did not achieve perfection. We did not use 
the same care as we are today exercising in the selection 
of a clean aggregate or a good mix. Neither Avere we 
so careful about striking off and finishing the surface. 



Concrete Roads and Pavements. 



37 



I believe I am safe in saving that the concrete road? 
we are buikling today are 25 per cent better than our 
first efforts. We have abandoned entirely the construc- 
tion of two-course roads built of crushed cobblestone, 
because of the difficulty of securing a suitable supply 
of properly graded material of this character. Crushed 
stone also contains a greater percentage of voids to be 
filled, and we have standardized on the single course 
road. 

"Any commimity that wants a good road, a road 
that is cheaper for even a short time under fairly heavy 
traffic than any other good road, a road that is inex- 
pensively maintained, a road that is sanitary and dust- 
less, a road that is not slippery, a road that affords good 
traction for any type of vehicle three hundred and 
sixty-five days in the year, a road that in the long run, 
say ten, fifteen, twenty years, and longer, is the cheap- 
est of all good roads, should investigate the merits of 
concrete. 

"The results we have obtained can be secured anv- 




Method of Mixing and Delivering. 



38 Concrete Roads and Pavements. 

wliere if strict attention is paid to detail, care used in 
the selection of good clean stone and sand, and the 
proper proportion of a standard brand of Portland 
cement used, coupled with good mixing and care in fin- 
ishing the surface so it will not be full of depressions. 
It will not pay to stint the amount of cement used if 
good results are expected, and there must be adequate, 
intelligent, and honest supervision." 

The following winter Mr. Hines spoke before the 
Pittsburgh Convention of the I^ational Association of 
Cement Users, from which address we quote : 

^'With four years' experience as a guide, we have 
demonstrated in Wayne County that a well-built con- 
crete road is a practical form of construction which 
merits and will receive a more extensive adoption. 
Every test to which our work has been subjected only 
emphasizes its strong characteristics. The points con- 
sidered are, initial cost, ultimate cost (which includes 
maintenance), sanitation and freedom from dust, good 
traction for all types of vehicles, smoothness and ease 
of construction. 

"The initial cost of a good concrete road is little, 
if any, greater than that of a first-class bituminous 
macadam road. One of the greatest fallacies indulged 
in by communities starting to improve their highways, 
is that cheapness in cost of original construction of 
roads means economy and that the highway official who 
can build the greatest area of roads at the least outlay 
per square yard, is working for the community's best 
interest. 

"On one of the main highways out of Detroit, 
Grand River Road, the first two miles is tar macadam. 
If someone had offered to build this road absolutely 



Concrete Roads and Pavements. 



39 




striking- Off the Surface. 



without one penny's cost to Wayne County, stipulating 
only that we should maintain it in a fairly average con- 
dition, at the end of eight years we would have been 
money ahead by rejecting the offer and building it of 
concrete under our present specifications. Of course, 
six years ago, when we built this road, we did not pos- 
sess this knowledge, but our experience was one of the 
reasons for abandoning the construction of this type of 
road and turning to concrete. When it comes to annual 
cost, the concrete road stands pre-eminent. With over 
sixty miles of concrete road in Wayne County, some of 
it in its fourth year, we have spent less than $300 on 
its surface for maintenance, and this is what makes this 
type of road the cheapest of all good roads. 

^^WoodAvard Avenue Koad, now in its fourth year, 
shows little or no signs of wear and it is not built 
nearly so well as our latest constructed concrete roads. 
A conservative estimate of traffic on this road shows 
that over 1,300,000 vehicles (more traffic than would go 



40 Concrete Roads and Pavements, 

over an ordinary country road in twenty years) have 
passed a given point, without the development of ruts, 
holes or bumps and with the expenditure of next to 
nothing for surface maintenance. On this same road, 
Woodward Avenue, adjoining our concrete at the 8-mile 
road, which is the Wayne and Oakland County line, 
Royal Oak Township this year built two miles of 
asphalt macadam at a cost of well over $1.00 per square 
yard. The first mile was opened for traffic August 17. 
On I^ovember 30 I went over this mile and counted 137 
holes from one foot up to four, five and six square feet. 
Fifteen men, a steam roller and a couple of teams were 
at work patching and repairing and the road is not four 
months old. 

''Whenever men interested in highway construc- 
tion get together they talk maintenance most emphatic- 
ally. While not belittling the principle of maintaining 
a road after it is built, it seems to me, with Wayne 
County's experience, it would pay other communities 
to adopt a form of construction on which it is not neces- 
sary to expend from $800 to $1,300 a mile yearly to 
keep it in fairly usable condition. Our concrete roads 
are sanitary, as there is no detritus from the road it- 
self ; there are few cracks and joints to hold dirt and 
animal droppings, and there is no dust. The drier the 
weather the less dirt on them, as vehicles do not track 
mud from unimproved cross-roads in dry Aveather. 
What little dirt is tracked on is immediately blown off 
or washed off by the first rain. 

''Our concrete roads have a gritty surface and are 
not slippery in any kind of weather, affording good 
traction for all kinds of vehicles. Horses find good foot- 
ing on them and automobiles do not skid in wet weather. 



Concrete Roads and Pavements. 41 

"It is not necessary to build concrete roads with 
any great amount of crown, and the tendency to drive 
in one track, so apparent on macadam roads by the 
formation of ruts, is eliminated, as the driver of a 
vehicle can sit comfortably in his seat, no matter on 
what part of the road he may be driving. Neither can 
a horse pick out the beaten track as on a gravel or 
macadam road. A crown of ^/4 inch to the foot dis- 
poses of the surface water and tends to distribute traffic 
over the entire surface of the road. 

"With all the other good points in its favor, con- 
crete can be handled with comparative ease, and provid- 
ing the work is carried on under skilled supervision, can 
be laid with a working force of relatively unskilled 
labor. It must be borne in mind, however, that the 
addition of a little cement to a quantity of stone and 
sand does not make concrete. There is no material 
which will respond so quickly to a little care, and if 
proper attention is given to the detail of mixing and 
curing, so well repay you in quality and permanence. 
With the foregoing in mind as to why we are con- 
tinuing to build concrete roads, I am going to take up 
a little more of your time and tell you how we are 
building them. 

"Drainage and good foundation are necessary for 
any type of road, and on a concrete road, the greater 
care that is taken in this respect, the better will be the 
final result. A well-drained, well-compacted sub-grade 
will eliminate cracks to a very large degree. 

^'One of the bad features alleged against concrete 
roads is the tendency to crack. In order to overcome 
this tendency, we prepare our sub-grade as carefully as 
conditions permit, making it flat and rolling it hard 



42 



Concrete Roads and Pavements. 



A' 




i.k 



Striking Off. 

and firm. Due to temperature changes and the absorp- 
tion of water, concrete is constantly in motion and the 
flat sub-grade tends to overcome frictional resistance 
and thereby prevents longitudinal cracking. On the 
first concrete road we built, we crowned the sub-grade 
to conform to the finished crown of the road and used 
what I term, for want of a better name, an inverted 
curb. On this road and on the first concrete road built 
on Michigan Avenue, where practically the whole road 
is built on a fill, we have developed more cracks than on 
all subsequent construction. These cracks, however, are 
well taken care of at a small expense, by the use of a 
hot refined tar and sand. On our concrete roads it is 
the repair of these cracks that has made up surface 
maintenance cost, and with a well drained, well rolled, 
firm sub-grade, cracks of all kinds are reduced to a 
minimum and not to be seriously considered. 

"We build our roads in 25-foot sections to provide 
for contraction and expansion, believing it wise to make 



Concrete Roads and Pavements. 43 

our lateral cracks beforehand so we can properly protect 
their edges from chipping and spalling. We are using 
a metal plate Avhich is a development of previous experi- 
ments. This plate is about 3/16 of an inch thick and 8 
inches wide, provided with shear members which tie it 
securely to the concrete base and wearing surface. It is 
shaped to conform to the crown of the finished road and 
two thicknesses of three-ply asphalted felt (about %- 
inch) are inserted between the two plates of each joint. 
By the use of these plates we have practically overcome 
the wear at the joints, which is the weakest point in the 
concrete road, besides securing a smooth, even, con- 
tinuous finish." 

Wayne County is poor in good road material and 
everything has to be imported. The best results have 
been secured from the use of washed gravel, ranging in 
size from %-inch to 1%-inch, and washed sand from 
%-inch to nothing. An effort is made to have the ma- 
terial well graded so as to secure a dense concrete. 
Freedom from loam, clay or other foreign matter is 
absolutely insisted upon. These people believe in a rich 
mix, using one part of cement to three parts of stone, 
with just a little more than enough sand to fill the 
voids in the stone. They believe that the detail of mix- 
ing and curing the concrete have been as great factors in 
their success as any other feature. 

The roads are constructed with a minimum thick- 
ness of 7 inches. After the sub-grade is prepared, side 
rails of 2x7 inch lumber are placed, protected on top 
by a 2-inch angle iron. The concrete is laid right on 
the natural subsoil, which is well sprinkled just pre- 
vious to the placing of the concrete to prevent the water 
in the concrete being absorbed. 



44 Concrete Roads and Pavements. 

A wet mix is used. 'No tamping is necessary, 
although a couple of men work in it with shovels. It 
is not considered wise or desirable to have the mortar 
and fine aggregate worked to the top as it i^ the stone 
vv^hich is wanted to receive the wear. After the con- 
crete is in place, no workman is permitted in any man- 
ner to disturb the finished surface by stepping in it or 
throwing anything on it. A plank trimmed to the 
curvature of the road and iron bound on the edges is 
used to give the road its proper shape. Two men saw 
this plank back and forth over the concrete, resting on 
the side rails or form board at the sides of the concrete, 
over which the strike-off rides smoothly. It is handled 
with sufficient care to eliminate the necessity for any 
considerable floating by the follow-up men. These fol- 
low-up men, or floaters, work on a bridge which rests 
on the form boards or rails at the side of the road so 
there is never any contact with the concrete. The flnal 
"smoothing up" is done with wooden floats of home 
manufacture. When the concrete has become suf- 
ficiently firm to permit the removal of the side rails, the 
finishers, to prevent a sharp division line between the 
concrete and gravel shoulders, pare off the outer edges 
which are formed next to the rails. 

Each day's work is finished up to an expansion 
joint, and no more than 20 minutes is permitted to 
elapse between batches during the day. The work of 
the day is covered with canvas, and the next day the 
canvas is removed, and to prevent the concrete from 
drying out too rapidly, it is covered to the depth of 
about 2 inches with any sand or loose soil that may be 
available. The concrete is sprinkled continuously for 



Concrete Bonds and Pavements. 45 

8 days and roads are not opened for traffic until at least 
two weeks after the last concrete is put in place. 

The trunk roads are built 16 feet wide of concrete 
and secondary roads 15 feet, with a minimum width of 
22 feet over all. These shoulders are usually built of 
limestone or gravel in two layers of 3 inches each and 
rolled Avith a 10-ton roller. This work is not started 
until the adjacent concrete is at least three weeks old. 

''We do all work ourselves under the day labor 
plan/' says Mr. Hines, "and during parts of our busy 
season employ as many as 1,200 workmen; handle from 
900 to 1,000 cars of materials a month and build a 
mile of road, in the aggregate, every three days. Ma- 
chinery plays an important part with us, as we do not 
believe that a man should be set at a task which a ma- 
chine can do as well or better. Stone, sand and cement 
are hauled from railroad sidings to the job by steam 
hauling engines or combination traction engines and 
rollers; graders, rooter plows and scarifiers are hauled 
in the same manner, doing the work of from 6 to 8 
horses, more efficiently and more rapidly. Each con- 
crete gang uses about 15,000 gallons of water a day, 
which is pumped from the nearest available source. 

''Two-inch pipe, with a tap every 400 feet, is laid 
along the road under improvement. Gasoline engines 
furnish the motive power and we have pumped water 
as far as six miles. Where we can find room along rail- 
road side tracks, we operate a Brown hoist, with a ton 
bucket for transferring stone and sand to our hauling 
wagons. Concrete is mixed in a mechanical batch 
mixer that travels under its own power, and from 
which a boom projects, capable of being swung in the 
arc of a semi-circle. Our men are housed and fed in 



46 



Concrete Roads and Pavements. 













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48 Concrete Roads and Pavements. 

camps along the roadside. We have worked out many 
other small economies, improvements and labor saving 
devices which tend to keep the quality up and the cost 
down. All work is specialized ; one crew prepares the 
grade; another gets the materials on the grade, whicii 
is done with such nicety as to make it usually unneces- 
sary to haul in extra sand or pebbles to make a properl;y 
proportioned batch ; another crew handles the concrete ; 
another builds the shoulders, etc. By so doing, the men 
become more efficient as they become familiar with 
their tasks and we secure more and better work out of 
them." 

As to the cost of the Wayne County roads, the com- 
missioners are frank in stating that they are trying to 
build for permanence and are not thinking so much 
about low first cost. They are not squandering money, 
however, and averaging the work done, and including 
all expenses whatsoever, the cost of these roads is 
about $1.50 per square yard, the average figure quoted 
elsewhere in this volume. In regard to the matter of 
cost, Mr. Hines made the following statement before the 
Western Society of Engineers : 

^'The question of cost, as I see it, is largely a local 
one. I think that in the building of the roads too much 
consideration has been paid to the man who attempts 
to build the greatest amount of yardage for the least 
amount of money, forgetting that cost is an annual 
affair rather than a first affair. We have built con- 
crete roads in Wayne County as low as $1.04 per square 
yard, figuring in the drainage, the engineering, the cul- 
verts, subgrading, and grading, — all those things, — fig- 
uring on the concrete yardage only ; and we have built 
them at a cost as high as $1.71. The conditions on a 



Concrete Roads and Pavemenis. 40 

given mile of road are not necessarily the same as on 
some other mile. We pay $1.00 per ton for washed 
and screened gravel. The lowest price that we have 
paid for washed and screened sand is 83 cents per ton. 
We have paid as high as $1.85 per ton for gravel and 
$1.55 per ton for sand. We cannot approximate costs 
under such conditions. We have hauled as short dis- 
tances as half a mile and as long distances as nine miles. 
The question of cost is something that must be settled 
in individual communities. I think our cost has been, 
on an average, about $1.50 per square yard. I do not 
think we shall ever be able to build at as low a cost as 
$1.04 again, and I think, under ordinary conditions, 
w^e shall not have to pay as high as $1.71 per square 
yard. We have an efficient organization and are put- 
ting all the money necessary (not with the idea of being 
wasteful) into making a good road, a durable road, and 
a road easily and cheaply maintained.'' 

The tables on pages 46 and 47 give figures on a 
nmnber of the different pieces of road built during 
1911. They do not include the cost of drainage. 



CHAPTEE IV. 
Cost of Concrete Eoads in Illinois. 

During the season of 1912 five sections of concrete 
road were constructed by the Illinois Highway Com- 
mission, and cost data obtained in the construction of 
these roads, together with data obtained in construction 
of macadam roads, makes it possible to estimate with 
reasonable accuracy the cost of concrete road construc- 
tion. The facts as here given are taken from the report 
of the Commission for 1912. 

While the data obtained in the construction of 
these Rye sections of concrete road would not be ade- 
quate as regards the cost of earth work and the hauling 
of materials, it is conclusive as regards the kinds of 
work which are distinctive of the concrete roads ; that 
is, the cost of mixing and placing the concrete and cost 
of expansion joints and of miscellaneous supplies. The 
cost of earth work and the cost of hauling materials 
for concrete roads will not differ from the cost of the 
same class of work on macadam roads. The table which 
gives an estimate of the cost of concrete roads is based 
on the information obtained in the construction of five 
sections of concrete road, so far as the cost of mixing 
and placing the concrete and the cost of expansion joints 
are concerned. But for the remainder of the items 
which enter into the cost of the concrete roads, such 
as earth work and hauling materials, the table is based 
on the data for the construction of macadam roads. 

In making this estimate, it is assumed that gravel 

(50) 



Concrete Roads and Pavements. 51 

concrete will be used and that tlie gravel will cost 
$1.50 per cubic yard, f. o. b. cars, at destination. The 
cost of hauling material is taken from a curve worked 
out by the department from data on hauling crushed 
limestone. But in making these estimates proper cor- 
rections have been made for the difference in weight 
per cubic yard of the two materials. 

It is also assumed that cement costs $1.20 per 
barrel, f. o. b. cars at destination, and no profits or 
overhead charges are considered in making up the 
table. 

The following explanation of the manner in which 
the cost of a square yard of 6-inch concrete roadway 
is determined will show in general how the table is 
compiled : 

The item ^^superintendence, watchman and miscel- 
laneous labor" is taken from the actual cost for these 
items on concrete work done by the State Highway 
Commission. 

The items "shaping road bed" and "trimming 
shoulders" are taken from a table of actual perform- 
ances. The data obtained in the construction of the 
macadam roads also shows the cost of loading material 
on wagons to be 10.7 cents per cubic yard, and the cost 
per cubic yard for hauling % niile is found from the 
curve. These two items added together and compen- 
sated for the difference in weight between gravel and 
crushed stone gives the item of loading and hauling 
materials. The other labor items are determined by 
the assumptions made as regards the cost of gravel and 
the cost of cement. The items "expansion joints," 
"coal, oil and miscellaneous supplies for mixer," "forms 
and other lumber," and "mixing and placing," are de- 



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(52) 



Concrete Roads and Pavements. 53 

termined from a table, which gives the cost of the work 
on the concrete roads constructed during 1912. 

Having determined the cost per square yard for 
the two thicknesses given, and for the four lengths of 
haul given, the cost per mile for the concrete roadway 
of varying widths is determined by multiplying the 
number of square yards in a mile of road of the given 
width by the cost per square yard. The table also gives 
the cost of a mile of concrete road 6 inches thick and 
10 feet wide, with 3 feet of macadam on each side of 
the concrete roadway. In computing this cost, the cost 
of the concrete roadway is determined as before ex- 
plained, and to that is added one-third of the cost of 
a mile of 12-foot macadam road. This cost of the 
macadam, alongside the concrete, is determined on the 
assumption that it is made two-thirds the thickness of 
a standard macadam road, and being one-half as wide, 
will therefore require one-third of the material and 
labor of a 12-foot macadam road. 

In the same manner the cost of a concrete road 
12 feet wide, with 2 feet of macadam along each side, 
is determined with the assumption that the cost of the 
macadam will be one-sixth the cost of a standard 1 2-foot 
macadam road. 

The details on the various roads built of concrete 
during the year are as follows : 

Cliandlerville-Beardstown Road^ Chandlerville 
Township, Cass Cou7ity. This consists of a section of 
concrete road constructed over a particularly sandy 
piece of road just outside the village of Chandlerville. 
The work was done very largely by subscriptions and 
the cost data herewith given is made up on a basis of 
the day labor price for this subscription work, which in 



Costs of Concrete Boads Constructed in Illinois in 1912. 



Road. 


McLean. 


DeKalb. 


Spring- 
field. 


Carlin- 
ville. 


Amt. of pavement (sq.yds.) . . 
Thickness 


5.000 
6 in. 
45 ft. 
V8 mile 

$1.02-1.06 
29 bbl. 


7.334 
6 1/2 in. 
12 ft. 
1/2 mile 

55 cents 
.31 bbl. 


5,594 
7 in. 
18 ft. 
Vs mile 

$1,021/2 
.29 bbl. 


7,111 

6 1/2 in. 

16 ft. 

Sand 1% 
mile; 
stone, 
V2 mi. 

98 cent*; 


Width 

Length ofi haul. 


Cost of cement 


Cement used per sq. yd 


.33 bbl. 



Cost of 


Iiabor and Supplies 


. 




Superintendence 


$ 140.00 


$ 200.00 

900.02 

69.75 

72.60 

596.02 
746.65 
187.07 
1,671.00 
1.250.00 
160.13 

32.00 
119.77 

Vi'.ie 

136.25 


? 202.00 
2 32*. 4 4 
211.38 

603.50 
644.25 
383.75 
1,622.01 
1,551.17 
206.74 

119.19 
18.33 


$ 157.50 
591 73 


Excavation 


Shaping roadbed 


307.41 


108 70 


Trimming shoulders and 
side roads 




Loading and hauling sand 
and stone, including re- 
handling 


267.34 

414.63 

110.26 

1.017.63 

1,547.15 

48.67 

30.75 
35.00 

45.18 


795 05 


Mixing and placing cone. . . 
Watchman and misc. labor. 
Cost of sand and stone f.o.b. 
Cost of cement f.o.b 


700.58 
131.46 
741.00 
2,307.90 
112.40 


Reinforcing steel 

Coal and oil for mixer and 

miscellaneous supplies. 

Forms and other lumber. . . 

Filling - expansion joints 


100.00 
1 

25.00 
31.75 


Carfares for men 

Pay for time of men coming 
and going 


1 








Total 


$3,964.02 


$6,194.42 


$5,794.76 


$5,803.07 





Cost per Square Yard for ^Labor and Supplies. 



Superintendence 


$0,028 


$0.0273 


$0.0361 


$0.0220 






0.1227 
0.0095 


b".64i5 


0.0840 




0.061 


0.0153 


Trimming shoulders and 








0.0099 


0.0378 




Loading and hauling stone 






and sand. Including re- 












0.053 
0.083 


0.0812 
0.1020 


0.1078 
0.1150 


0.1120 


Mixing and placing cone. . . 


0.0986 


Watchmen and misc. labor.. 


0.022 


0.0255 


0.0682 


0.0184 


Cost of sand and stone f.o.b. 


0.204 


0.2280 


0.2897 


0.1050 


Cost of cement f.o.b 


0.309 


0.1700 


0.2772 


0.3246 


Expansion joints 


0.010 


0.0218 


0.0369 


0.0156 


Reinforcing steel 








0.0140 


Coal and oil for mixer and 










miscellaneous supplies.. 


0.006 


0.0044 


0.0213 


0.0034 


Forms and other lumber. . . 


0.007 


0.0163 


0.0033 


0.0047 


Filling expansion joints 












0.010 












Total 


$0,793 


$0.8186 


$1.0352 


$0.8176 







(54) 



Concrete Roads and Pavements. 55 

many cases was more than the work was worth on 
account of its intermittent nature. 

The pavement constructed is a concrete roadway 
16 feet wide and is 6 inches thick, gravel being used 
for the concrete. 

The following table is an itemized statement of 

the cost of this work: 

Amount of pavement laid 1,470 sq. yds. 

Thickness of pavement 6 inches 

Width of pavement 16 feet 

Length of haul for materials i/^ mile 

Cost of cement per barrel $1,13 and $1.20 

Amount of cement per sq. yd. of pavement. . . 0.31 bbl. 

Cost of Labor and Supplies. 

Superintendence $ 50.00 

Excavation (donation, value estimated) 71.73 

Shaping road bed 29.75 

Loading and hauling stone and gravel 173.21 

Mixing and placing concrete 155.08 

Cost of sand and stone 370.85 

Cost of cement 553.03 

Total $1,403.65 

Cost Per Square Yard for Labor and Supplies. 

Superintendence $0,034 

Excavation (donation, value estimated) .048 

Shaping road bed .020 

Loading and hauling stone and gravel .118 

Mixing and placing concrete .105 

Cost of stone and gravel .257 

Cost of cement .378 

Total $0,960 

Sycamore-De Kalh Road, De Kalh Township, De 
Kalh County. The coimtry is fairly level, and only a 
small amount of earth work was necessary. The soil 
is a black loam clay, and the road was well drained. 
The concrete roadway was made 12 feet wide and 6^2 
inches thick, with macadam shoulders 2 feet wide on 
each side of the concrete roadway. The concrete wa^ 



56 Concrete Roads and Pavements. 

made of gravel and sand which was purchased in the 
market, and the cost of the entire improvement was 
paid from the regular road and bridge fund. 

A part of this road was reinforced with %-inch 
square twisted 10-foot bars placed crosswise of the 
pavement, and a part of the road was reinforced with 
ISTo. 26 A wire mesh made by the American Steel & 
Wire Company. The mesh is made up of No. 6 wire 
with 2-inch mesh, and was in strips 34 inches wide, 
which were laid crosswise of the road, overlapping 
about 2 inches. 

Beginning with the section ending at station 27 + 
45 and continuing to the section ending at station 
11+65, the reinforced sections alternate with plain con- 
crete sections as follows: 

The sections are numbered at the edge near the 
expansion joint and each section is the part of the pave- 
ment between two expansion joints. The various sec- 
tions follow each other in the following order and are 
numbered as here given: 

1^0. 1. Reinforced crosswise with %-inch bars 2 
feet center to center, 12 sections. 

ISTo. 2. Reinforced crosswise with %-inch bars 4 
feet center to center, 12 sections. 

ISTo. 3. Plain concrete, 12 sections. 

No. 4. Reinforced with No. 26 A wire mesh, 4 
sections. ^ 

The mesh reinforcement cost $1.84 per square of 
100 square feet. The bar reinforcement cost 2 cents 
per pound, f. o. b. Chicago Heights, or 16.8 cents per 
bar 10 feet long at De Kalb. 

The following table is an itemized statement of 
the cost of this work : 



Concrete Roads and Pavements. 57 

Amount of pavement laid 7,334 sq. yds. 

Thickness of pavement 6^^ inches 

Width of pavement 12 feet 

Length of haul for materials ^2 mile 

Cost of cement per barrel $0.55 

Amount of cement per sq. yd. of pavement 0.31 bbl. 

Cost of Labor and Supplies. 

Superintendence % 200.00 

Excavation 900.02 

Shaping road bed 69.75 

Trimming shoulders and side roads 72.60 

Loading and hauling sand and stone, including re- 
handling 596.02 

Mixing and placing concrete 746.65 

Watchman and miscellaneous labor 187.07 

Cost of sand and stone f. o. b. DeKalb 1,671.00 

Cost of cement f. o. b. DeKalb 1,250.00 

Expansion joints 160.13 

Reinforcing steel (bars, $294.00; mesh, $42.93) 336.93 

Coal and oil for mixer and miscellaneous supplies. . . . 32.00 

Forms and other lumber 119.77 

Car fares for men 51.16 

Pay for time of men coming and going 138.25 

Total $6,531.35 

Cost Per Square Yard for Labor and Supplies. 

Superintendence $0.0273 

Excavation 1227 

Shaping road bed 0095 

Trimming shoulders and side roads 0099 

Loading and hauling stone and sand, including re- 
handling 0812 

Mixing and placing concrete 1020 

Watchman and miscellaneous labor 0255 

Cost of sand and stone f. o. b. DeKalb 2280 

Cost of cement f. o. b. DeKalb 1700 

Expansion joints (materials only) 0218 

Coal and oil for mixer and miscellaneous supplies 0044 

Forms and other lumber 0163 

Total $0.8186 

Peoria Road, Springfield Township, Sangamon 
County. The soil at the north end is black loam, and 
farther along clay and sandy soils are encountered. The 



58 Concrete Roads and Pavements. 

road leads through rolling country, and a considerable 
amount of excavation was found to be desirable. 

The construction work began during the fall of 
1912, and about one-half mile of pavement was laid. 
The roadway is gravel concrete 18 feet wide, 8 inches 
thick at the middle and 6 inches thick at the edge. 
On the section completed, armored expansion joints 
were used, but on the section to be built in 1913, it is 
planned to use creosoted block expansion and plain 
expansion joints filled with asphalt pitch. 

The following table of costs applies to the work 
which was completed in the fall of 1912. A considera- 
ble amount of material was on hand at the close of the 
season, to be carried over and used in 1913 : 

Amount of pavement laid 5,594 sq. yds. 

Thickness of pavement 7 inches 

Width of pavement 18 feet 

Length of haul for materials % mile 

Cost of cement per barrel. ^IMVz 

Amt. of cement used per sq. yd. of pavement. . 0.29 

Cost of Labor and Supplies. 

Superintendence .$ 202.00 

Shaping road bed 232.44 

Trimming shoulders and side roads 211.38 

Loading and hauling sand and stone, including re- 
handling 603.50 

Mixing and placing concrete 644.25 

Watchman and miscellaneous labor 383.75 

Cost of sand and stone f. o. b. Springfield 1,622.01 

Cost of cement f. o. b. Springfield 1,551.17 

Expansion Joints 206.74 

Coal and oil for mixer and miscellaneous supplies... 119.19 

Forms and other lumber 18.33 

Total .$5,794.76 

Cost Per Square Yard for Labor and Supplies. 

Superintendence $0.0361 

Shaping road bed 0415 

Trimming shoulders and side roads 0378 

Loading and hauling sand and stone, including re- 
handling 1078 



Concrete Roads and Pavements. 69 

Mixing and placing concrete 1150 

Watchman and miscellaneous labor 0686 

Cost of sand and stone 2897 

Cost of cement 2772 

Expansion joints 0369 

Coal and oil for mixer and miscellaneous supplies 0213 

Forms and other lumber 0033 

Total $1.0352 

Town Square, Mt. Hope Townsliip, McLean 
County. In 1907 a macadam road was constructed in 
the village of McLean extending from the town limits 
up to the town square, the town square itself not being 
improved. This town square consists of a triangular 
park surrounded by a roadway, along which are the 
principal business houses of the village. The improve- 
ment consists of a concrete roadway 45 feet wide, with 
a total area of 5,000 square yards. The concrete was 
made 6 inches thick and was constructed from gravel, 
to which was added a small amount of Joliet crushed 
stone. 

The following table is an itemized statement of the 
cost of this work : 

Amount of pavement laid 5,000 sq. yds. 

Thickness of pavement 6 inches 

Width of pavement 45 feet 

Length of haul for materials Vs mile 

Cost of cement per barrel $1.02 and $1.06 

Amt. of cement used per sq. yd. of pavement. 0.29 bbl. 

Cost of Labor and Supplies. 

Superintendence $ 140.00 

Shaping road bed 307.41 

Loading and hauling sand and stone, including re- 
handling 267.34 

Mixing and placing concrete 414.63 

Watchman and miscellaneous labor 110.26 

Cost of sand and stone f. o. b. McLean. . ; 1,017.63 

Cost of cement f. o. b. McLean 1,547.15 

Expansion joints 48.67 

Coal and oil for mixer and miscellaneous supplies.., 30.75 



60 Concrete Roads and Pavements. 



Forms and other lumber 35.00 

Filing expansion joints next curbs 45.18 



Total $3,964.02 

Cost Per Square Yard for Labor and Supplies. 

Superintendence $0,208 

Shaping road bed .061 

Loading and hauling stone and sand, including re- 
handling .053 

Mixing and placing concrete .083 

Watchman and miscellaneous labor .022 

Cost of sand and stone .204 

Cost of cement .309 

Expansion joints .010 

Coal and oil for mixer, and miscellaneous supplies.. .006 

Forms and other lumber .007 

Filling expansion joints next curbs .010 



Total $0,793 

Burhe Lane Road, Carlinville Township, Macou- 
pin County. The soil is a black loam, and the road 
was fairly level, but was thickly shaded and had been 
one of the worst roads in the community on that ac- 
count. It had been filled in places with stone, brick 
and cinders, making what little excavation had to be 
done, expensive. The improvement consists of a con- 
crete roadway 16 feet wide and 6% inches thick. 
Crushed stone for the concrete was furnished from the 
Southern Illinois Penitentiary and sand was hauled 
from a creek west of Carlinville. 

From the C. & A. tracks to the culvert at about 
station 8, the middle of the road was reinforced by 
%-inch square twisted bar 6 feet long, running cross- 
wise and placed one foot from center to center. This 
was made necessary by a newly filled sewer trench 
under this section of road. 

The following table is an itemized statement of 
the cost of this road : 



Concrete Roads and Pavements. 61 



Amount of pavement laid 7,111 sq. yds. 

Thickness of pavement 6V2 inches 

Width of pavement 16 feet 

Length of haul for materials 16 feet 

Sand 1^/^ miles 

Stone li^ miles 

Cost of cement per barrel f. o. b. Carlinville. ... 98 cents 

Amt. of cement used per sq. yd. of pavement. . . . 0.33 bbl. 

Cost of Labor and Supplies. 

Superintendence $ 157.50 

Excavation 591.73 

Shaping road bed 108.70 

Loading and hauling sand and stone, including re- 
handling 795.05 

Mixing and placing concrete 700.58 

Watchman and miscellaneous labor 131.46 

Cost of sand and Stone f. o. b. (stone freight only, 

sand free) 741.00 

Cost of cement f. o. b Carlinville 2,307.90 

Expansion joints 112.40 

Reinforcing steel 100.00 

Coal and oil for mixer, and miscellaneous supplies. . . 25.00 

Forms and other lumber 31.75 

Total $5,803.07 

Cost Per Square Yard for Labor and Supplies. 

Superintendence $0.0220 

Excavation 0840 

Shaping road bed 0153 

Loading and hauling stone and sand, including re- 
handling 1120 

Mixing and placing concrete 0986 

Watchman and miscellaneous labor 0184 

Cost of sand and stone f. o. b. (sand free at pit) 1050 

Cost of cement f. o. b. Carlinville 3246 

Expansion joints 0156 

Reinforcing steel 0140 

Coal and oil for mixer, and miscellaneoui supplies... .0034 
Forms and other lumber 0047 

Total $0.8176 




(62) 



CHAPTEE Y. 

Othek Examples of Co]s^crete Eoads. 

MilivauJcee County Roads. Milwaukee County, 
Wisconsin, started in 1912 on the construction of a com- 
prehensive system of concrete roads, under the super- 
vision of Mr. H. J. Kuelling, formerly with the Wis- 
consin State Highway Commission. 

The work is all one-course work and is laid in 
widths of 16 to 18 feet with an average thickness of 7 
inches. The specifications for the most part provide for 
a crown of % inch to a foot, which in some cases will be 
carried into the sub-grade. On the work done during 
1912 the making and placing of the concrete was done 
by contract and in some instances the grading as well; 
in some cases, however, the commissioner did his own 
grading by force account, and all culverts are being 
made by a gang of men under his direct control. 

On the contract work the county furnished all ma- 
terials, the cement being delivered to the job by the 
dealer, and the contractor being required to haul his 
stone and gravel. Water is also supplied by the county 
and has furnished one of the difficult problems of the 
construction of the roads. The difficulty of securing 
suitable w^ater as needed has led the county to buy all 
its water from the city, piping it out to the jobs through 
2-inch pipes. If necessary, pumps are used to secure 
sufficient pressure. 

The specifications state that concrete shall consist 
of one part cement, two parts sand and four parts stone, 

(63) 



64 Concrete Roads and Pavements. 

the parts determined by volume. In regard to tlie ma- 
terials, however, the commissioner has done some ex- 
perimenting and an effort vt^as made in some cases to 
secure a pit run material which would have approxi- 
mately the correct proportions of sand and gravel with- 
out grading. The plan at present is to screen the gravel 
as it comes from the pit through a %-inch screen, all 
below this size being used for sand and above this size 
up to 2% inches being considered gravel. These are 
then combined in proportions of 2 to 4, the combination 
being effected in some cases at the pit and in other 
cases on the job. The specifications require that con- 
crete shall be mixed in mechanical batch mixers. 

As a result of this experiment, Mr. Kuelling says 
that two of the biggest mistakes anyone can make in 
this class of work are : First, to take the gravel directly 
from the pit, and second, the use of dirty materials. 
The pit run gravel showed a great variation, and almost 
all of it with an excess of sand, making a larger amount 
of cement necessary than where the materials are care- 
fully graded. The county has now bought rights to cer- 
tain gravel pits,, and has put in screening plants, so that 
materials are carefully screened, cleaned and graded. 

The roads have scarcely any tendency to steep 
grades, but the disposition of the commissioner is to 
keep the grade down to 4 per cent in any case. 

The method of construction is, in the first place, 
to stake a 2x7 inch plank at the outer edge of the pro- 
posed road, the upper edge of the plank to conform with 
the finished grade of the work. The concrete is then 
placed in position ; and while the specifications call for 
tamping, the mix used is so wet that very little tamping 
is necessary. Two men are employed on each job whose 



Concrete Roads and Pavements. 65 

special duty it is to strike off the surface with a strike 
board, this board having a curvature corresponding to 
the crown of the road and its ends resting on the planks 
at the sides. Under extreme heat, or when overtaken 
by rain, the work is covered with canvas or other suit- 
able means and is thus protected until it takes its initial 
set. After a number of hours it is covered with a light 
layer of earth, approximately one inch thick, and is 
sprinkled each day for five days. The earth covering 
is removed in from 10 to 14 days. 

Expansion joints are put in transversely every 25 
feet. These expansion joints consist of two Baker 
dividing plates, having shear members which extend 
into the concrete and anchor them firmly to it. Between 
the two plates is placed two layers of tar felt in 7-inch 
width, thus making the joint the full depth of the road. 

The work of the new Chicago road was somewhat 
out of the ordinary, because of the fact that it had to be 
done on both sides of an inter urban railway track. 
This complicated the work, as the track had to be 
kept open for the passage of cars, and it was neces- 
sary to find storage room for materials on contiguous 
private property. The mixer also had to be located at 
such points as could be found convenient and longer 
hauls of the concrete were made than would otherwise 
be allowed. 

The equipment of the plant consisted of a Smith %- 
yard mixer mounted for end discharge, and delivering 
the concrete into Briggs carts, in which it was conveyed 
to the point of deposit. The mixer aimed to cover 
about 1,000 feet to a set-up, making the longest haul 
500 feet in each direction. Up to a haul of about 300 
feet, two of the Briggs carts were used, while on longer 




(66) 



Concrete Roads and Pavements. 



67 



hauls a third one was called into requisition. The ma- 
terials Avere Avheeled to the mixer by wheelbarrows from 
stock piles near at hand and dumped into an automatic 
loader. 

Six men were employed on Avheeling, three men on 
the mixer, including the engineer, five men placing con- 
crete, three men on the carts, one man making up and 
placing joints, and two men working ahead cleaning up 
the roadway and j^lacing forms. This gang covered 400 
to 450 square yards per day. 

The work on the Janesville road was of the stand- 
ard type, 18 feet wide. Here a different method of con- 
struction w^as employed, the materials being delivered 
in the middle of the road and thrown directly into the 
loading hopper of the mixer and in turn discharged by 
the mixer directly at the point of deposit. For this 




W^ithdrawing the Stakes W^hich Hold the Joints. 



68 Concrete Roads and Pavements. 

purpose a Chain Belt mixer was arranged on trucks for 
end discliarge and provided with a swinging steel chute 
so that it distributed concrete over the entire width of 
the roadway. Moves of about 5 or 6 feet were made at 
frequent intervals. 

The crew on this work consisted of 17 laborers, one 
engineer and two foremen. At the time these notes were 
taken the gang was progressing at about the rate of 100 
lineal feet per day. 

The work on the Kilbourn Road was also 18 feet 
wide and the methods of construction were similar to 
those employed on the Chicago Road, the mixing plant 
being stationary and the concrete being delivered to the 
work in Briggs %-yard concrete carts, with a limit of 
haul of 400 feet. 

The crew consisted of 8 men wheeling and shovel- 
ing, 3 men on mixer, 4 men spreading and laying, 3 
men on carts, 2 men on joints, 4 men unloading carts, 1 
foreman, and boy. 

These roads are costing in the neighborhood of 
$1.00 per square yard, exclusive of the grading, dis- 
tributed as follows : 

Cement $0.33 

Gravel and stone 16 

Labor and hauling .43 

Joints ; 06 

Inspection and water 02 

Total $1.00 

At Winona, Minn. In 1912 Winona County, 
Minnesota, let contracts for 16 miles of concrete roads, 
at a cost of $116,000. This price was about $10,000 
less than the lowest bid on the same roads in macadam, 
by the same bidders, and figures out to about $7,250 per 
mile, although the grading varied to such an extent as 



Concrete Roads and Pavements. 69 

to make an average figure of little value. The specifica- 
tions provide that the sub-grade shall be brought to a 
firm, unyielding surface where fills are made, by rolling 
each 6 inches of fill. x\ll soft or spongy spots, vegetable 
or perishable matter is removed and replaced by the 
same material as that of which the sub-grade is com- 
posed. When heavy clay soil is encountered it is pro- 
vided that the sub-grade shall be excavated 4 inches be- 
low grade and shall be filled with crushed rock or gravel 
rolled to a thickness of 4 inches. 

The concrete roadway proper is laid on the center 
line of the road to a width of 8 feet and a thickness of 
6 inches, with a cro^vn of 1 inch. The concrete is laid 
in sections 35 feet in length, separated by %-inch ex- 
pansion joints, these extending through the entire thick- 
ness of the slab and being filled after construction with 
a bituminous filler. The expansion joints are formed 
by three strips of steel, cut to the size and shape of the 
cross-section of the road, and with projections at the 
ends to permit of their removal. After the concrete has 
set the middle strip is first removed, after which the 
other strips can readily be taken away. 

The surface of the roadway is finished with a 
wood float, and where the grades exceed 4 per cent the 
surface is grooved with a grooving tool in both direc- 
tions, the longitudinal grooves being 10 inches apart 
and the transverse grooves 3 inches apart. The grooves 
are %-inch wide and %-inch deep. 

The specifications provide that the sand shall be 
graded up to % inch and shall not contain clay or loam 
in excess of 4 per cent. The gravel provided for is com- 
posed of hard, dry pebbles not larger than 1% inches 
nor smaller than % inch. 



YO 



Concrete Roads and Pavements, 



The materials are pilt onto the road in the propor- 
tions of 1, 2 and 4, the sand and gravel being measured 
loose in measuring boxes and a sack of cement being 
considered equal in volume to one cubic foot. 

The specifications call for a mixture of such con- 
sistency that it will quake slightly when tamped, but 
not so thin that it cannot be troweled to the required 
cross section. The mixing is done by a Koehring street 
paving mixer of the self -tractive type, carrying a swing- 
ing boom which covers the entire width of the roadway 
for the delivery of the concrete. The machine is 
equipped with an end-loading bucket holding the full 
capacity of the drum, with a water measuring tank 
which supplies the proper amount of water to each 
batch, and a water tank mounted on the frame to supply 
water for the steam boiler. This machine discharges at 
the rear and is provided with traction drive for moving 
it along the roadway so that it may always be located 
just at the point where concrete is to be placed. 

The specifications provide that the contractor shall 
wet and tamp the sub-grade to a proper form imme- 
diately before the concrete is placed and that the con- 
crete shall be placed to full width and thickness of the 
roadway at one time and well tamped and struck off 
with a template and floated to the entire cross-section 
with wood floats. 

After the concrete is set, it is covered with about 
one inch of wet earth and gravel and is kept free from 
travel for a period of two weeks. 

On one side of the concrete roadway is a shoulder 
of gravel which is rolled to a thickness of G inches at 
the edge of the concrete, 4 inches at a point 4 feet 



Concrete Roads and Pavements. 71 

away, and is feathered off to a point 6 feet from tlie 
edge of the concrete. 

Where it is necessary to carry flood waters over the 
roadway, especially on side hills, the concrete is placed 
the fnll width of the roadway in the form of a ''dip," 
somewhat similar to the old-fashioned ''thank-you- 
ma'am" of the dirt road. This dip has a depression 
of 6 inches to 10 feet ont of grade line, and is given a 
slight skew to the lower side of the road so as to carry 
off the water more readily. 

The qnantity of concrete used is 14.81 cubic yards 
per 100 feet, or 782 cubic yards per mile. 

The contract price as given includes all grading, 
of which there is over 40,000 cubic yards, also culverts 
and a small amount of concrete and rip-rap retaining 
walls. 

In a paper before the Minnesota Society of En- 
gineers and Surveyors, Mr. O. B. Leland, engineer in 
charge of the Winona work, stated: ''The grading is 
costing on an average a little over 40 cents a yard. The 
concrete culverts cost about $50 each for 18-inch, $65 
each for 24-inch, $85 for 30-inch, and $105 for 36-inch, 
placed in the road. The average cost of grading per 
mile, including culverts, is $1,500. The macadam 
costs about 25 cents per lineal foot of road, and the 
concrete 90 cents per lineal foot of road. We are get- 
ting 16 miles of good road for $116,000." 

An Experimental Road in California. An experi- 
mental concrete road, 3,000 feet long and 18 feet wide, 
was constructed in the fall of 1912 between Sacra- 
mento and Riverbank, Cal., passing through the River- 
bank subdivision of the West Sacramento Company. 
The company has large holdings in this vicinity, in the 



T2 Concrete Roads and Pavements. 

development of which the road problem led it to ex- 
periment with ten various sections of concrete pave- 
ment to determine its applicability to local climatic, 
traffic and subgrade conditions. The engineers also 
wished to determine the most economical design. It is 
believed the comparatively uniform temperatures in 
California will minimize to a large extent expansion 
and contraction difficulties. The details as here given 
are taken from Engineering Record of March 8, 1913. 

On the western half of the roadway the sub-grade 
material is a heavy clay loam soil, resembling an adobe. 
The eastern half of the slab was constructed over an 
old macadam roadway. The subgrade was excavated 
and trimmed to the required grade and crown. It was 
then thoroughly compacted by sprinkling and rolling 
with an 8-ton roller. All portions of the old macadam 
road in fill were well tamped. In all cases the subgrade 
was well moistened just previous to placing the con- 
crete to prevent abstraction of water from the concrete. 

All work was given a crown by sloping the surface 
from the center to each side of the roadway at the rate 
of % inch per foot. Local experience with other types 
of pavement has led to a standardization of this fea- 
ture. Longitudinally the roadway is practically level. 

Four of the sections were reinforced with a light 
wire mesh having a cross-sectional area less than 0.1 
per cent of the area of the concrete. While this is 
sufficient to reinforce the slab against temperature and 
shrinkage stresses, it was thought that it might prove 
valuable in holding the road intact. Rectangular and 
triangular mesh reinforcement of the American Steel 
and Wire Company and the Clinton Wire Cloth Com- 
pany was used. 



Concrete Roads and Pavements. 73 

Four types of expansion joints were experimented 
with. In the first, lines of oiled surfaces were spaced 
at 10, 20, 30 and 40-foot intervals squarely and diag- 
onally across the pavement. Tar-paper joints were 
laid 10 and 20 feet apart on square and diagonal lines. 
In another section %,-inch spaces were filled with 
bitumen at intervals of 25 and 40 feet on square and 
diagonal lines, transversely with the pavement. A 
fourth type consisted of %-inch spaces at 30-foot inter- 
vals, squarely across the pavement, with the edges pro- 
tected by soft steel plates 4 inches wide and held in 
place by anchor bolts. A section 217 feet long was laid 
without expansion joints. 

Various types of finished surface were used. These 
included roughening with wire brooms, pitting by an 
embossed tamper, checkering and grooving with checks 
6 inches square, plain concrete, sanding and covering 
the surface with a A-inch coat of bitumen and ^ato- 
raas rock screenings. 

Concrete was mixed in a %-yard gasoline engine- 
driven Ransome mixer on the sidewalk area alongside 
the road and wheeled to place in 10 cubic foot buggies. 
At each position of the mixer about 300 feet of road 
were laid. 

Three classes of fine aggregate were used: First, 
Sacramento River sand, dredged near the site of the 
work, having very fine, much rounded quartz grains. 
It contains a considerable proportion of mica flakes, but 
very little sediment. Second, Yuba River sand, dredged 
from the Yuba River at Marysville, having medium- 
sized quartz grains, somewhat rounded. It contains 
little mica, but small amounts of sediment and small 
balls of mud. Third, Natomas fine crushed rock, vary- 



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Concrete Roads and Pavements. 75 

ing from % inch to dust. It is very sharp and carries 
so much fine stone dust that it is difficult to determine 
the percentage by sedimentation. 

Tests were made of the three classes of fine aggre- 
gate and for comparative purposes strength tests were 
made on Ottawa sand. Voids were determined by 
thoroughly compacting 100 cubic centimeters of dry 
sand, then adding 100 cubic centimeters of water and 
reading the amount absorbed by the sand. Briquettes 
were made of standard Ottawa sand and cement, as 
w^ell as of the materials to be tested. The quantity of 
water, however, was varied in order to get a mortar in 
each case as nearly as possible with the same consis- 
tency as that made from the standard sand. As com- 
pared with the standard sand there was required for the 
Sacramento River sand nearly double the amount of 
water, for the Yuba River sand 50 per cent more water 
and for the ^Natomas fine crush about the same quan- 
tity. Tensile tests were made after seven days. It 
will be noted that the ]N'atomas fine crush made a con- 
siderably stronger mortar than the standard Ottawa 
sand. In all cases the coarse aggregate was material 
obtained by crushing the tailings from the gold dredg- 
ings in the vicinity of Folsom. The dredgings vary 
from pebbles the size of an egg to boulders a foot or 
more in diameter, composed of a hard and tough, al- 
tered andesite. As placed on the market the rock is in 
four sizes: 2% to IV2 inches, 11/2 to % inches, % to 
% inch; screenings, % inch to dust. Only the last 
three sizes were put into the road concrete. The per- 
centage of voids in the IV2 to %-inch size ranged from 
46.7 to 48.5 loose; the % to %-inch size ranged from 
43.3 to 39.7. By mixing these two sizes in various 



76 Concrete Roads and Pavements, 

proportions the voids were reduced to about 40 per 
cent. 

With the object of obtaining a dense concrete with 
a minimum amount of cement, careful tests of the voids 
in the various materials were made by weighing the 
water filling the interstices in a cubic-foot box. Tests 
for determining the relative proportions of the differ- 
ent materials which would make the densest aggregate 
were also made by thoroughly mixing the dry materials 
loose. This was accomplished by shaking and rolling 
the various mixtures in a large canvas and weighing 1 
cubic foot of the material to determine which mixture 
had the greatest weight per unit of volume, and hence 
the smallest proportion of voids. 

Messrs. Haviland, Dozier and Tibbetts, consulting 
engineers of San Francisco and Sacramento, had 
charge of the design and construction. 

Concrete Roads in Ohio. The state of Ohio com- 
pleted in 1912 over 40 miles of state roads in various 
parts of the commonwealth. These in most cases were 
in short stretches, put in very largely for experimental 
purposes, to test out various methods of construction, 
and also to give the people an opportunity to pass judg- 
ment on concrete highways. 

An idea of the cost of the work done may be gath- 
ered from a resume of a few of the contracts, as follows : 

1.61 miles, 16 feet wide $12,285 

2.14 miles, 14 feet wide 21,000 

1.70 miles, 14 feet wide 14,480 

.34 miles, 16 feet wide 5,750 

1.41 miles, 12 feet wide 11,970 

3-92 miles, 16 feet wide 40,670 

2.05 miles, 16 feet wide 31,925 

1.25 miles, 14 feet wide 15,645 

4.14 miles, 16 feet wide 38,930 



Concrete Roads and Pavements. Y7 

While it would be difficult to arrive at a very just 
average from these figures, they show a total of 18. 5 G 
miles, with an average width of very nearly 15 feet, at 
a total cost of $192,655. This works out to an average 
of $10,380 per mile of 15-foot roadway. This is mani- 
festly a much higher price than it will be necessary to 
pay when a definite type of construction is decided upon 
and a broad policy outlined, so that contracts can be let 
for longer stretches of road. The work of administra- 
tion, of supervision and of preliminary preparation are 
of course much higher when the contracts are small and 
scattered; and then, too, it is more than likely that 
many of these contractors were unfamiliar with this 
class of work and felt it necessary to make a price to 
cover unlooked-for contingencies. The experience of 
the year will enable some of the more enterprising 
ones among them to work out methods which will 
greatly reduce the cost on subsequent contracts. 

All the work listed above is given a bituminous top 
surface, coal tar paving pitch being used principally, 
though asphalt was applied in some cases. It was ap- 
plied at the rate of % gallon per square yard, and 
while still soft a top dressing of sand was spread over it. 

Concrete was laid from 6 to 8 inches thick, the 
specifications calling for batch mixing. The propor- 
tions were about 1 :1^ :3%, although tests were made 
at various times to endeavor to keep the mix intelli- 
gently proportioned according to the materials in hand. 
The specification for aggregates was as follows : 

Great care should be used in selecting the aggregates for 
concrete. Careful tests will be made of the materials in order 
to determine their qualities and the grading necessary to se- 
cure maximum density. 

Fine aggregate shall consist of sand, crushed stone, or 
gravel screenings, passing when dry a screen having 14-inch 



Concrete Roads and Pavements. 



diameter holes. It is preferred that the fine aggregate con- 
sist of silicious material and be graded from fine to coarse. 

Coarse aggregate shall consist of crushed stone, gravel 
or slag that will pass through a screen having openings 2^ 
inches in diameter and be retained upon a screen having 
openings %-inch in diameter. Bach particle shall be clean, 
hard, durable, and free from all deleterious material. All soft, 
flat or elongated particles must be removed and it is required 
that the material be graded from fine to coarse. 

Joints were made every 30 feet. These were made 
in a variety of ways, including wood, asphalt filler, 
Baker's armor plates, etc. 

The specifications called for a snfiiciently true sur- 
face so that it would nowhere show a variation of more 
than % inch from a template or straight edge. 

Gravel shoulders were built at the sides, 4 feet 
wide, and rolled down to a thin edge at the outside. 

Roads in Washington, The state of Washington 
is experimenting with concrete roads, as stated by the 
highway commissioner in his report for 1912. 

In Lincoln county, the commissioners are building 
a half mile of plain concrete roadway. The first course 
is a l:3y2:Y mixture, 4 inches thick; the top course is 
a 2 :3 :6 mixture 1-1^/2 inches thick. This road is cost- 
ing about 90 cents per square yard. 

Lewis county is building 2.8 miles of plain con- 
crete roadw^ay under the permanent highway law and 
one mile from the county road and bridge fund. The 
first course is a 1 :3 :5 mixture, iYz inches thick, the top 
course is a 1 :1 :1 mixture 1% inches thick, with expan- 
sion joints every 50 feet. Both asphalt and tarred 
paper were used in expansion joints. This road is cost- 
ing on an average $1.30 per square yard. 

Franklin county is building a concrete pavement 
with a bituminous wearing surface. The concrete base 



Concrete Roads and Pavements. 79 

is one course of about 1:2:4 mixture, 5 inches thick; 
the top course is one-third gallon of asphalt oil per 
square yard, with screenings to take up the oil; expan- 
sion joints every 50 feet. The concrete base is costing 
$1.08 and the top dressing $0.17 per square yard. 

Kittitas county is building a concrete pavement 
with Dolarway top. The pavement is one course of a 
1:2%:5 mixture, 5 inches thick, and the top course of 
Dolarway mixture and screenings is V4, inch thick. Ex- 
pansion joints every 50 feet. This road is costing 
$1,125 per square yard. 

Pierce county is building a two-course concrete 
roadway known as Granocrete. The first course is a 
1 :3 :6 mixture, 4% inches thick, and the top course is a 
1 :li/2 mixture- — one part cement to 1% parts of stone 
chips, 1% inches thick. Expansion joints are put in 
from 2 to 50 feet apart. This road is costing $1.40 per 
square yard. 

Cost of Owatonna Road. There was completed 
in 1912 near Owatonna, Minn., a stretch of 1,100 
feet of concrete road on the main traveled highway be- 
tween Owatonna and Albert Lea, a road over which a 
considerable amount of automobile traffic passes. The 
concrete is 8 feet wide, 6 inches thick, with 1-inch ex- 
pansion joints every 50 feet, these expansion joints 
being filled with pitch. Corrugations to prevent slip- 
ping occur at 4-inch intervals. 

The road .is over a sand hill, most of it in a cut 
where sand washed badly, making it impossible to pre- 
serve any shape to an ordinary road. It is expected 
that this road, aside from giving much better service, 
will do away with heavy maintenance charges. The road 



80 Concrete Roads and Pavements. 

has little or no crown, but has clay and gravel shoulders 
on each side sloping down to an edge 3 feet away. 

Had it not been for the sand on which this piece 
of road was built and the necessity of hauling clay for 
the sides it could have been built for 90 cents per run- 
ning foot. The actual cost, however, was about $1.03, 
as shown in the following itemized statement of cost. 
The item of grading has not been taken into account in 
these figures. 

Labor $276.00 

Cement 464.76 

Gravel 162.85 

Lumber 33.72 

Total $936.73 $ 936.73 

Deduction for cement 68-76 

Deduction for extra labor 86.25 

$155.01 $ 155.01 

Deducted total $ 781.72 

Building gravel sides cost 350.00 

Total cost of road $1,131.72 

Common labor received $2.00 a day, a man and 
team $4.00 ; cement was delivered at the work at $1.43 
per barrel and gravel delivered at the work at -1.00 per 
yard. 

Roads in Idaho. The following is the report of a 
typical day's work on concrete roads in Ada county, 
Idaho : 

Three men wheeling, two men shoveling gravel for 

mixer at $2.75 for eight hours $ 13.75 

Two men wheeling sand, ditto 5.50 

One wheeling cement, one loading cement, ditto 5.50 

One mixer man on loading and tending water 2.75 

One engineer (sub-foreman) and delivery operator 3.00 

Three men setting forms, $2.75 for eight hours 8.25 

One sub-foreman 3.00 

One superintendent 5.00 



Concrete Roads and Pavements. 81 

Engineering and field supervision 25.00 

One water team and man 7.25 

•005 depreciation on equipment 10.00 

One timekeeper 3.00 

Cost of materials — 

1,200 square yards crushed gravel and sand at 7 cents. 84.00 

91 barrels Red Devil Portland Cement, at $2.60 236.60 

5 gallons gasolene for mixer at 23 cents, oil 15 cents. . . 1.30 

Total $419.90 

600 square yards of concrete, 7 inches thick, on crushed 

gravel well rolled, cost per square yard $ .70 

At Sehewaing, Mich. During the summer of 
1912, one mile of experimental road was constructed at 
Sebewaing, Michigan, half of which consisted of a con- 
crete pavement 9 feet 2 inches wide, of an average 
thickness of 6% inches, with 3 -foot gravel shoulders on 
each side, and one-half mile of tar macadam, 9 feet 
wide with dirt shoulders 5% feet wide on each side. 
The contract for both stretches of pavement was let to 
the same firm. The total cost of the one-half mile of 
concrete roadwav was $3,592 and of the tar macadam 
$3,753 ; a first-class concrete pavement in this case ac- 
tually costing $161 less than first-class tar macadam. 
The road leads to a sugar beet factory and during the 
fall was subjected to heavy traffic. Keports from Sebe- 
waing are to the effect that the concrete is in first-class 
condition, as good as when laid, whereas the tar ma- 
cadam is commencing to show wear. 



CHAPTEK YI. 

Some Data on City Pavements. 

At Mason City, Iowa. Mr. P. P. Wilson, city 
engineer of Mason City, Iowa' has made an extensive 
study of concrete paving and lias put down successive 
stretches of this pavement through a series of years, re- 
vising his specifications somewhat each year in the light 
of experience. Mr. Wilson makes this statement : 

^^It is my opinion from my observation and expe- 
rience that a Portland cement concrete pavement, prop- 
erly laid in an up-to-date manner, with first-class ce- 
ment, good, clean, sharp sand, and good, clean, hard 
stone, with proper allowance made for contraction and 
expansion, with the edges of the expansion joints pro- 
tected with softened steel plates, said protection plates 
anchored into the concrete on each side of the expansion 
joint, the pavement to be kept wet and protected from 
the sun at least eight days after it is laid, so that it 
cures out slowly, certainly warrants the use of cement 
paving on account of its first cost, cheapness to main- 
tain, cleanliness of the streets, and the small expense to 
repair when it becomes necessary to cut holes. 

''In constructing a first-class cement pavement the 
first requirement is to have first-class material; sec- 
ondly, to have a first-class, up-to-date set of plans and 
specifications ; and lastly, honest, rigid and close follow- 
ing of these specifications in every detail." 

Mason City has adopted the two-course method of 
construction on account of the soft stone that is at hand 

(82) 



Concrete Roads and Pavements. 83 

in the locality, making a very satisfactory base but 
being entirely nnsnited to making a hard wearing sur- 
face. 

The Mason City specifications as used by Mr. Wil- 
son during 1912 are given in Appendix C. 

At Fort Smith, Ark. During 1912 the Board of 
Improvement of Paving District 'No. 5, at Fort Smith, 
Ark., constructed by force account about 100,000 square 
yards of concrete pavement at an average cost of "69.4 
cents per square yard. This cost includes the removal 
of about % yard of earth per square yard of pavement 
in the grading and the rolling of the sub-grade. It also 
includes a 10 per cent allowance for depreciation on 
equipment, but no charge for superintendence. The 
pavement was 6 inches thick, of the 1-course type, un- 
reinforced, and was made of 1 :2 :4 concrete. 

The construction of this pavement was described 

by the engineer, Mr. George Myers, in Engineering and 

Contracting. The main equipment consisted of a No. 

23 Chicago batch concrete mixer and %-yard Briggs 

one-horse carts, besides the usual grading implements. 

Portland cement on an average cost $1.18 per barrel; 

gravel and sand averaged $1.25 per cubic yard; broken 

stone, crusher run, averaged $1.20 per cubic yard. The 

above prices are for materials delivered on the job. 

Common labor was paid for at the rate of 15 to 20 

cents per. hour; enginemen at 25 cents; foreman, $125 

per month, and teams 35 cents per hour. 

The cost of the concrete was as follows : 

Per cu. yd. 

iy2 bbls. cement at $1.18 $1.77 

0.4 cu. yd. sand at $1.25 50 

0.9 cu. yd. broken stone at $1.20 1.08 

Mixing, carting, laying and cleaning up 49 

Total .$3.84 



84 Concrete Roads and Pavements. 

This figures out 64 cents per square yard ; adding 5 
cents per square yard for grading and .4 cent per square 
yard for rolling makes the total cost 69.4 cents per 
square yard. 

The method of construction was as follows : 

The sub-grade was shaped to conform to and be 6 
inches below the finished pavement. The concrete 
mixer and material were placed about midway of each 
section of the work^ but off to one side. The carts 
brought the concrete to one end of the work and it was 
deposited between %x6-inch steel templates 20 feet 
apart, the entire width of the roadway. The concrete 
was quite wet and was tamped by means of a heavy 
steel-shod straight edge, and then floated with a 2x4-inch 
yellow pine float, 22 feet long, in order to reach well 
beyond the templates. Segments of red building paper 
were placed next to each template before the concrete 
was placed and as soon as possible the template was 
withdrawn, leaving a contraction joint. The adjoining 
section was then laid in the same manner. An expan- 
sion joint was left every 60 feet. 

At Lynn, Mass. In 1911 the city of Lynn, Mass., 
removed an old macadam road and replaced it with a 
one-course concrete pavement. The sub-base was made 
the same shape as the finished surface and was thor- 
oughly rolled with a 12-ton roller. 

The concrete was mixed in a batch mixer in the 
proportions one part Portland cement, two parts sand 
and four parts graded broken stone. The mixture was 
of a quaking consistency. Along each curb an expan- 
sion joint was made by means of a %-inch band. There 
were no joints made across the street. Although the 
pavement is 2,000 feet long, no cracks are evident in it. 



Concrete Roads and Pavements. 85 

Before the concrete hardened the surface was roughened 
hy hrooming. All travel was kept off the street for one 
week. 

The street is a fine example of permanent pave- 
ment. It was built by contract for $1.70 per square 
yard, including grading. 

At MarsJialltown, Iowa. In 1911 Marshalltown 
did a small amount of concrete paving, and in 1912 
there were 60,000 square yards put down, the contract 
price on this being $1.08 per yard. This was consid- 
ered a low price by the city engineer, and was accounted 
for in part by the fact that the contractor was not 
required to give a large maintenance bond, a rigid test 
of materials and inspection of the work being insisted 
upon. Materials were also secured at very reasonable 
rates. 

An inspector was stationed at the mixer and an- 
other worked with the spreading and finishing gang. 
Each carload of cement was submitted to the standard 
tests of the American Society of Civil Engineers and 
the commissioners insisted that the gravel and sand 
grade up to specifications. 

The combined sand and gravel was taken from the 
bed of the Iowa river and from old river channels in 
the valley inside the city limits. The aggregate was 
pumped and discharged over a one-quarter inch screen, 
separating the stone and sand. The small cost of pump- 
ing and screening, and the short haul from gravel beds 
to mixer, made the low cost of these materials an impor- 
tant item in the contractors' estimates. 

A feature of the construction was the arrangement 
of the expansion joints and the method by which the 
filler was placed in them. All of the pavement was laid 



86 Concrete Roads and Pavements. 

in residence streets. Most of it was 30 feet wide. The 
curb was not combined with the gutter but was poured 
separately. In addition to a joint % inch wide next 
to each curb, a longitudinal joint ^A inch wide was 
placed in the center of the street. Transverse joints also 
% inch in width, were spaced at 15 foot intervals, di- 
viding the pavement into blocks 15 feet square. All 
these joints extended down to the sub-grade. Those 
next the curbs were filled with an asphaltic filler. The 
longitudinal and transverse joints were filled with rub- 
beroid, or a good grade of tar paper. This paper was 
put in while the pavement was being laid. 

The method of placing the filler in the cross and 
lengthwise joints is a new one that has been adopted in 
few other cities. The pavement was laid only half the 
width of the street at a time. The paper was placed 
in the transverse joints as the concrete was spread and 
tamped. A strip of rubberoid 8 inches wide was held 
in place alongside a plank 5 feet long, while the con- 
crete was being spread on both sides of the plank. The 
plank was then lifted, leaving the filler in place, with 
about an inch of it projecting above the wearing sur- 
face. After the pavement set, the protruding edge of 
the paper was trimmed with a sharp shovel flush with 
the top of the pavement. The longitudinal joint was 
established while the first half of the paving was being 
laid along one side, by staking a line of planks, 7 inches 
wide, along the center of the street. When the concrete 
had begun to set the planks were removed and strips of 
rubberoid were tacked to the edge of the finished side 
from which the planks had been taken. The top edge 
of the paper was set flush with the surface. The other 
half of the street was then paved. 



Concrete Roads and Pavements. 8Y 

The city engineer originated the idea of the joint 
in the center of the street after he had observed, when 
inspecting concrete pavement in other cities, that where 
there was no such joint the pavement had cracked in 
more or less zigzag lines longitudinally near the center 
of the street.* The central joint checks any transverse 
cracks from extending farther across than the center. 
The crosswise and lengthwise joints divide the pave- 
ment into 15-foot blocks, making it easy, if a block 
becomes defective from any cause, to remove it and lay 
new concrete without affecting the rest of the pavement. 

Wanting to make a comparative test with another 
kind of filler for the longitudinal joint, the city en- 
gineer secured waivers from property owners in one 
block, and, instead of placing rubberoid in the central 
joint, the joint was cut and the cut was filled with pitch. 
The object aimed at was to test the wearing qualities of 
the edges of the central joint when different fillers are 
used. Eighteen months use shows that some of the 
edges of the longitudinal joints filled with rubberoid 
are chipping, but in most places they show no more 
wear than the rest of the pavement. 

This pavement consists of a 5-inch base, composed 
of 1 part cement, 3 parts sand and 5 parts gravel. The 
2-inch wearing surface is composed of 1 part cement to 
2 parts of sand. The wearing surface is laid as soon 
as the base is spread, tamped and brought to grade, and 
is roughened with a coarse broom. 

At Alpena, Mich. The following figures are taken 
from the report of the city engineer of Alpena, Mich., 
on work done during the summer of 1911 : 

*This probably indicates not the need of a central joint, but 
the need of greater strength at this point. 



88 Concrete Roads and Pavements. 



Water Street Pavement. 

No square yards 707 

Crushed stone % 49.00 

Gravel 70.00 

Cement, 274 bbls., at $1.20 net 328.80 

Asphalt filler 2236 ■ 

Catch basins 23.28 

Armor plates for expansion joints 21.12 

Lumber for expansion boards, etc 9.04 

Labor, men 331.00 

Labors teams 96.00 

Total amount $ 950.60 

Cost per square yard, $1,295. 

Washington Avenue Pavement. 

No. square yards 3,545 

Crushed stone $ 165.00 

Gravel 304.00 

Cement, 1,406 bbls. at $1.20 net 1,687.20 

Asphalt filler 77.49 

Steel for curb protection 12.60 

Armor plates for expansion joints 62.50 

Catch basins 58-20 

Lumber for expansion boards, curbing, etc. . 45.37 

Labor, men 1,449.25 

Labor, teams 767.00 

Total amount $4,628.61 

Cost per square yard, $1,305. 

Fletcher Street Pavement. 

Amount paved by city, square yards 1,286 

Crushed stone $ 88.00 

Gravel 149.00 

Cement, 668 bbls 801.60 

Asphalt filler 37.24 

Armor plates for expansion joints 28.16 

Steel for curb protection 3.85 

Catch basins 27.36 

Lumber, expansion boards, curbing, forms, 

etc 21.67 

Labor, men 1,045.25 

Labor, teams 252.00 

Total amount $2,454.18 

Cost per square yard, $1.39. 

Chisholm Street Pavement. 
No. square yards 6,518 



Concrete Roads and Pavements. 89 

Crushed stone $ 272.00 

Gravel 537.00 

Cement, 2,607 bbls 3,128.40 

Asphalt filler 143.39 

Armor plates for expansion joints 147.40 

Steel for curb protection 16.80 

Catch basins 69.84 

Lumber, expansion boards, curbing, forms, 

etc. 83.92 

Labor, men 2,288.25 

Labor, teams 860.00 

Total amount $7,547.00 

Cost per square yard, $1,158. 

Mill Street Pavement. 

No. square yards 1,098 

Crushed stone $ 53.00 

Gravel 93.00 

Cement, 440 bbls 528.00 

Asphalt filler 39.00 

Armor plates for expansion joints 27.50 

Lumber, expansion boards, curbing, forms, 

etc 25.87 

Labor, men • 545.00 

Labor, teams 206.00 

Total amount $1,517.37 

Cost per square yard, $1,382. 

At Waterloo, Iowa. During the summer of 1912 
the first concrete pavements were laid in Waterloo, 
Iowa. Two alleys, each in a different part of the city, 
were paved. The specifications called for a two-course 
pavement. In one alley 4-inch base and l^-inch wear- 
ing surface was specified ; the base to consist of 1-3-6 
stone concrete, or 1-5 gravel, and the top 1-2 screened 
gravel, passing % inch sieve, the top coat to be ap- 
plied within 40 minutes of the time of placing the base. 
In the other alley the wearing surface was increased to 
2 inches on account of heavier traffic. The surface coat 
was mixed wet enough so that the contour of the pave- 



90 Concrete Roads and Pavements. 

ment could be forced by drawing a templet over it, after 
which the surface was troweled and then broomed with 
an ordinary broom. 

Expansion joints were provided every 25 feet 
transversely, and contraction joints midway between the 
expansion joints. Expansion joints were made by plac- 
ing two rows of vitrified brick blocks, separated by a 
board % inch thick, end to end across the width of the 
alley. These brick were placed after the base was put 
in, and were embedded in the base so that the upper 
part of the bricks conformed to the curve of the fin- 
ished surface of the pavement. The top or wearing sur- 
face was mixed wet enough so that the mortar flowed 
into the cracks between the ends of the bricks, holding 
them firmly in place. The spacing board was taken 
out as soon as the concrete had hardened sufficiently, 
and none of the bricks were displaced in removing the 
board. The joint was afterwards filled with an asphalt 
filler. • 

The pavements are required to be guaranteed for 
a period of one year. Both alleys seem to be in very 
good condition now, and have not shown any signs of 
wear or deterioration. The cost was $1.12 per square 
yard for the 5i/2-inch pavement and $1.25 for the 6-inch 
concrete. 

At Aledo, III. During the year 1912 a compar- 
atively large yardage of concrete pavement with a 
wearing surface of bitumen and sand was laid at Aledo, 
Illinois. Throughout the business section of the town 
a strip of brick pavement 6 feet wide w^as laid between 
the concrete pavement and the curbs. The contract 
price for the brick pavement on a 6-inch 1-2-4 concrete 
base with 1-inch sand cushion was $1.62. The contract 



Concrete Roads and Pavements. 



91 



price for the concrete pavement consisting of 6 inches 
of 1-2-4 concrete was 86 cents per square yard. The 
bitumen for the wearing surface was furnished the eon- 
tractor by the city. The contractor furnished sand and 
labor and laid the wearing surface for 10 cents per 
square yard. Allowing 20 cents per gallon as the cost 
of bitumen, this would make the total cost of the con- 
crete pavement approximately $1.06. 

VihrolitJiic Concrete Pavement. — This name is a 
term applied by R. C. Stubbs, a contracting engineer of 
Dallas, Texas, to a class of pavement put down in va- 
rious parts of Texas, and described by him in a paper 
before the Xational Association of Cement Users. The 
distinctive feature of this method is the use of a vibrator 
on the surface of a concrete pavement to bring the con- 
crete to a dense and even texture. 

The plan followed by Mr. Stubbs is to prepare the 
sub-grade as for any other pavement, after which the 
aggregate is hauled in and stored on the sub-grade. A 




Laying Vibrolithic Pavement. 



92 Concrete Roads and Pavements. 

traction concrete mixer is then brought in, with charg- 
ing bucket to receive the material and a chute to dis- 
charge the concrete. 

Concrete is composed of one part Portland cement 
and five parts aggregate — sharp sand and gravel — the 
portion passing a i/4-inch screen not to exceed 40 per 
cent, nor be less than 33 per cent, using as much water 
in mixing as the mass will retain without draining after 
depositing. The concrete comes directly along the chute 
to the street and is immediately raked to approximate 
grade. 

After an advance of a few feet, the surface is 
brought to a float finish by means of long-handled floats. 
Immediately upon this surface there is thrown a coating 
of crushed granite, graded from % to 1% inches. This 
stone is applied until surplus matrix has been taken up. 

This surface is then ready for vibration. The first 
part of this operation is to place platforms along or 
across the street, made up of %x4 inch strips cleated /4 
inch apart. Each platform is 20 inches wide and as 
long as desired, cleats projecting 1 inch along one side, 
the forward platform cleat projection lapping back onto 
another platform. When two or three platforms have 
been placed, a vibrator mounted on rollers is rolled onto 
the first platform and passing along from one to the 
other as they are put to grade, and the concrete is 
brought to a very high state of density. 

The construction of these vibrators was not gone 
into in detail by Mr. Stubbs, as he states that any device 
producing a vibration will answer the purpose, but the 
illustrations will give some idea of the type used by him. 
One of these he describes as simply a high-speed single- 
cylinder 5-liorsepower motor with out-of-balance fly 



Concrete Roads and Pavements. 93 

wheel. He states that thickness of mass, area covered 
or affected, thickness of platform boards, weight of 
vibrator, rate of vibration, and force of blow delivered, 
mnst all be taken into consideration in order to secure 
best results. 

As the work progresses, the platforms are brought 
forward and the granite surface of street is immediately 
covered with sharp sand and wetted. This is the first 
operation and completes a stone 6 inches thick, com- 
posed of 1 to 5 concrete, top 1 to 1% inches loaded with 
stone of high abrasive resistance — a street wdth un- 
equaled load-carrying capacity. The surface being com- 
posed of granite, all parts have an equal resistance to 
abrasion. The granite being forced into the concrete 
with vibration cannot be gotten out, but must wear out. 

The vibrators being mechanical, they can be relied 
upon to treat all parts alike, the operator's duty being 
simply to roll them over platforms to insure a concrete 
of equal and even texture. This evenness of texture 
gives uniform power to overcome internal stresses. 
High density means greater strength and a reduction of 
contraction and expansion factor from .0000065 to 
.0000032. 

Two or three days later the sand is swept off the 
surface into the gutter with stiff wire brooms, and %- 
inch Tarvia A is poured at a temperature of 150 degrees 
F. and leveled with rubber rakes. Immediately behind 
the levelers a coating of hard stone ^A to % inch is 
spread in sufficient quantity to thoroughly coat the 
pitch. Upon this is spread the sharp sand that has 
been swept into the gutter. The surface is then rolled 
with a 500-pound hand roller and street is held until 
concrete is 7 days old and then opened to traffic. 



94 



Concrete Roads and Pavements. 



The object in placing this coat so soon is to retain 
the original moisture in the concrete, that the process 
of hydration may be complete. Pitch may not adhere 
well to a moist mortar, but takes a firm hold on the 
granite surface. 

After 30 days' traffic the- surface irons down 
smooth, the small stone protects the pitch, while the 
sand fills the interstices, producing a very tough sur- 
face which will show a thickness of about % inch. 

''I provide for contraction joints only," says Mr. 
Stubbs ; ^^that is, I do not use bituminous joints to take 
care of expansion as well as contraction, finding that 
expansion comes from two causes — absorption and rise 
of temperature, and that contraction comes from five 
or more causes, the first being contraction from shrink- 
age during the first period of hydration. Other causes 
of contraction are not necessary to mention here, it 
being only necessary to consider the fact that contrac- 
tion comes before expansion. Therefore, if the slab 




Vibrator in Foreground. 



Concrete Roads and Pavements. 95 

contains a contraction stress throughout its mass suf- 
ficient to strain the growing bond, this stress will be re- 
lieved by small cracks at irregular intervals following 
lines of weakness. 

"My plan contemplates these cracks and forces 
them to come in straight lines wherever desired, by 
placing thin wooden planes %x3 inches on edge upon 
the prepared sub-grade in such manner that they will be 
buried in the concrete and will occupy the bottom half 
of concrete cross section. 

"Within 48 hours after the concrete has been laid, 
thin straight lines of relief will appear over the breaker 
strips. In this way the street is laid monolithic, no 
stone being permitted of greater size than whose strength 
will take care of its stresses, there being so general a 
distribution of breakers that no relief line gets of 
greater size than 1-16-inch, which is barely noticeable. 
I prefer this kind of joint because they do not wear 
off on edges like a filled joint and are more economical 
than an armored joint. 

"I did not adopt this joint until I had proved the 
contraction and expansion factor varied inversely with 
the density, and would not use relief lines in other than 
highly dense concrete. If this crack is to be %-inch 
or greater, as it would naturally be with poured or 
porous concrete, I would not advise its use." 

Cost of Pavement at Boise. The city of Boise, 
Idaho, has over 85,000 square yards of concrete pave- 
ment in service, the cost of the various sections of which 
is shown in the accompanying table. It is all one-course 
work, with surface finished with wood float. The mix- 
ture used is 1 :3 :7, and the price of cement is figured 
at $2.75 per barrel and sand and gravel at $1.00 per 



96 Concrete Roads and Pavements. 

cubic yard. The price does not include grading. The 

thickness on all the work is 6 inches, except the first 

one, which is 8 inches. 

Contract price 
Total Sq. Yds. per sq. yd. 

20,183.92 $1,155 

6,877.92 1.10 

27,018.00 1.09 

27,847.36 1.15 

3,482.12 1.04 



CHAPTEE VII. 

Reinforced Concrete Pavements. 

Reinforced concrete j^avements have been built in 
a number of localities, and with seemingly excellent re- 
sults, though the term of experience has scarcely been 
sufficient to determine whether their behavior or life 
are superior to that of ordinary concrete. It is easily 
conceivable that in building over fills, or otherwise un- 
stable gTOund, reinforcement would be a decided advan- 
tage in helping to distribute the load and thus prevent 
an undue concentration of weight on any one part 
of the sub-base. For pavements exposed to a constant 
heavy traffic, such as in the vicinity of plants where 
heavy machinery is manufactured, and the like, rein- 
forcement ought also to add materially to the life of 
the structure. 

One advantage claimed for reinforcement is that it 
serves to make of the pavement a more homogeneous 
mass. It is well known that the ratio of expansion 
and contraction of concrete depends to a considerable 
extent upon the proportion of cement contained. With 
a lean mixture as a base, therefore, covered by a rich 
top coat, the two courses will have different coefficients 
of expansion, with a consequent tendency of the two 
courses to crack apart. The introduction of reinforce- 
ment will to a certain extent counteract this tendency 
and help the two courses to act as a unit. 

One decided advantage claimed for a reinforced 
pavement is that it will prevent cracks due to expansion 

97 



98 Concrete Roads and Pavements. 

and contraction, and at the same time allow of a mnch 
wider separation of expansion joints. The first wear 
of a pavement usnally comes at the joints, or at cracks 
which develop after the pavement is laid. If these 
cracks can be reduced in number or entirely eliminated, 
and the distance between joints increased with safety, 
the reinforcing ought to be well worth while. 

One of the most usual methods of reinforcement is 
by the use of a sheet of wire mesh laid on the base 
course of concrete and tamped so that at least 50 per 
cent of the wire is covered. The reinforcement should 
preferably be placed with the longitudinal wires parallel 
to the center of the pavement, and covering the space 
between joints completely but not extending across the 
joints. The sheets of fabric should lap at least 1 
inch at the sides and 12 inches at the ends. Wire mesh 
may also be used for a one-course pavement, placed 2 
inches below the surface. In cases where reinforcing is 
required because of unusually unsatisfactory conditions 
of soil, the kind and location of reinforcing will have to 
be specified by the engineer for each location. 

Following are given a number of examples of re- 
inforced concrete pavements and the data concerning 
them: 

One of the first pavements constructed using a re- 
inforcement was laid at Plymouth, Wis., during the 
ssummer of 1910. Approximately 11,000 square yards 
were laid at that time at a cost of $1,235 per square 
yard including the grading. This pavement consisted 
of what is known as a two-course type, the base being 
made 5 inches thick and the top or wearing course iVz 
inches thick, making a total of 6V2 inches. The specifi- 
cations called for a concrete mixture in the proportions 



Concrete Roads and Pavements. 99 

of 1 13% ^6 for the base, the crushed stone to be free 
from dust and of varying sizes, all of which shall pass 
through a 2-inch ring and be held on a %-inch ring, the 
sand to be of such a size as will pass a %-inch square 
mesh. The top or wearing course consisted of 1 part 
of cement to IV2 parts of crushed granite, the granite 
to be properly graded from dust to % inch in size. 
After placing the bottom course, triangle mesh rein- 
forcement ^N^o. 7 was laid, the longitudinal wires being 
placed crosswise of the street, after which the wearing 
course was placed before the base had taken any appre- 
ciable set. 

The top course was troweled to a smooth finish 
and while still soft, granite screenings varying in size 
from 1/4 to % of an inch were scattered over the entire 
surface, the idea being to produce a surface that w^ould 
be practically smooth and at the same time one that 
would not be unnecessarily slippery. Expansion joints 
were placed every 40 feet across the pavement and also 
along the gutters. On streets having street car tracks, 
joints were also placed on each side of the track at 
the end of the ties. These joints were made by using 
1x8 inch cypress boards for forms, these boards being 
allowed to remain in the work and form the filler for 
the joints. Engineers have rej)orted this pavement to be 
in excellent condition after two and one-half years' 
wear. It was designed by Mr. W. G. KichofPer, consult- 
ing engineer of Madison, Wis., who also supervised the 
work. 

During the year 1911, Sheboygan, Wis., had ap- 
proximately 15,000 square yards of reinforced concrete 
pavement laid and during 1912 approximately 45,000 
square yards. The base consisted of 5 inches of con- 




100 



Concrete Roads and Pavements. 101 

Crete mixed in the proportion of 1 part of Portland 
cement, 3 parts of sand and 5 parts of crushed limestone, 
and was laid 5 inches thick at the center of the street 
and 3 inches at the curbs. The wearing surface was 1% 
inches thick and consisted of 40 per cent of Portland 
cement, 50 per cent of granite screenings and 10 per 
cent of torpedo sand. The granite screenings were 
graded to 20 per cent having a size of 1-16 to ^A of an 
inch and 30 per cent % to % of an inch. Triangle 
mesh N'o. 7 was laid between the wearing surface and 
the base, the longitudinal wires being placed crosswise 
of the street. The wearing course was floated by means 
of a wood float after which the surface was broomed 
transversely to give a slightly roughened surface. The 
pavement was sprinkled for seven days and no teams 
were allowed upon the same for ten days. One-inch 
expansion joints filled with asphalt were constructed 
along the curbs and every 40 feet across the street. 
These pavements were designed by City Engineer C. Y. 
Bowley, the contract price being $1.20 per square yard. 
The City of Fond du Lac, Wis., has made extensive 
use of concrete pavements, both plain and reinforced, 
having constructed during 1908 approximately 17,300 
square yards of plain pavement at an average price of 
$1,325 per square yard, and in 1909 approximately 
69,200 square yards at an average price of $1,235 per 
square yard. Since 1910 their concrete pavements have 
all been reinforced, using triangle mesh '^o. 7 for a 
width of 18 feet down the center between curbs, the 
principal reason for using the reinforcement being to 
eliminate the longitudinal cracks that formed in the 
plain pavements along the center line of the street. Por 
the year 1910 the average price for 44,300 square yards 



102 Concrete Roads and Pavement's. 

was $1,177 and for 1911 the average price of 11,000 
square yards was $1.25. An additional 8,000 square 
yards were laid during the year 1912. All pavements 
carry a five year guarantee, so that for the first five 
years at least there will be no maintenance charges. 

The usual type of combination curb and gutter is 
first constructed, after which the center portion of the 
street is excavated and rolled to the proper elevation. 
Upon this foundation is laid a 5-inch base course con- 
sisting of 1 part of Portland cement, 2% parts of sand 
and 5 parts of clean crushed limestone, 4 inches being 
laid first, upon which is placed the wire fabric rein- 
forcement, the longitudinal wires running crosswise of 
the street, and immediately thereafter is placed the ad- 
ditional 1 inch of concrete. The wearing surface is 
immediately applied and consists of 1% inches of a 
mixture of 1 part of cement, 1 part of clean sharp 
sand and 1 part of crushed granite, this granite consist- 
ing of sizes ranging from dust to % of an inch. The 
surface is then troweled and before hardening it is 
roughened by brushing crosswise with an ordinary 
street broom. Expansion joints are placed along each 
gutter and every 50 feet across the street and have a 
width of % of an inch. The forms for the expansion 
joints are allowed to remain in place until the concrete 
is hardened, after which they are removed and the joint 
is filled with an asphalt preparation. The surface is 
kept wet for one week and then the street is thrown 
open for trafiic. 

The pavements have been designed and the con- 
struction supervised by J. S. McCullough, city engineer 
for Fond du Lac. 

During the year 1912, Superior, Wis., laid 9,602 



Concrete Roads and Pavements. 103 

square yards of reinforced concrete pavement designed 
by City Engineer E. B. Banks. The base consisted of 
6 inches of concrete mixed in the proportion of 1 part 
of Portland cement, 2% parts of sand and 5 parts of 
crushed stone. The top or wearing course is 1% inches 
thick and consists of 1 part Portland cement, 1 part 
of sand and 1 part of crushed trap rock varying in size 
from % to % of an inch. The reinforcement used was 
triangle mesh wire fabric, style 29, placed with the 
longitudinal wires crosswise of the street and extending 
from curb to curb. The first 4 inches of the base were 
placed upon the rolled foundation and upon this was 
laid the reinforcement, after which the additional two 
inches of the base were laid. Immediately upon this 
completed base was placed the wearing course, which 
was troweled and roughened by brushing with a street 
broom. One-half inch expansion joints were placed 
along the curbs and across the street every 24 feet. 
The finished pavement cost $1.29 per square yard ex- 
clusive of the excavation, the material and labor costs 
being as follows : 

Cement, per barrel $1.35 

Sand, per cubic yard 75 

Crushed stone, per cubic yard 1.65 

Common labor, per day 2.50 

The City of St. Johns, Mich., laid during 1912 
approximately 15,000 square yards of reinforced con- 
crete pavement consisting of a base 5 inches thick mixed 
in the proportion of 1 part of Portland cement to 7 
parts of gravel including sand. The top or wearing 
course is 2 inches thick mixed in the" proportion of 1 
part of Portland cement to 3 parts of clean sharp sand. 
Triangle Mesh 'No. 29 was used as a reinforcement, the 
same being placed between the base and wearing courses. 



104 Concrete Roads and Pavements. 

Expansion joints were constmcted along the curbs and 
across the street every 30 feet, all joints being pro- 
tected with the Baker armor plate. This pavement was 
designed and supervised by E. G. Hulse, city engineer. 
A very successful reinforced concrete pavement has 
been laid in Hamtramck, Mich, (a suburb of Detroit), 
the same having been designed and constructed by the 
R. D. Baker Company, Detroit, Mich. During the 
year 1912, 15,000 square yards were laid, having a base 
5 inches thick consisting of a concrete mixture of 1 part 
Portland cement, 3 parts of sand and 6 parts of crushed 
stone. The wearing course is 2 inches thick, mixed in a 
proportion of 1 part Portland cement, 1 part of sand 
and 2 parts of crushed granite having a size not to ex- 
ceed % inch. The reinforcement used was triangle 
mesh 'No. 28, placed between the base and top course 
and laid with the longitudinal wires at right angles 
to the center line of the street. Expansion joints were 
placed along the curbs and every 30 feet across the 
street, and were protected by means of the Baker armor 
plates. The cost of the finished pavement was $1.35 per 
square yard, exclusive of excavation, the material and 
labor costs being as follows : 

Cement, per barrel $1.02 

Sand, per cubic yard 75 

Crushed stone, per cubic yard 1.15 

Crushed granite, per cubic yard 3.15 

All above being f. o. b. cars,Hamtramck. 
Common labor cost $2.60 per day. 

The City of Port Huron, Mich., laid about 9,000 
square yards of reinforced concrete pavement in the 
year 1912. This pavement had a total thickness of 7 
inches, consisting of a 5V2-inch base and a lV2-inch 
wearing course. The concrete for the base was mixed 1 



Concrete Roads and Pavements. 105 

part Portland cement to 5 parts of river run gravel. 
The wearing course consisted of 1 part cement, iy2 
parts sand, and 1% parts of %-incli crushed field stone. 
Triangle mesh reinforcement xnTo. 4 was placed between 
the top and bottom courses. Expansion joints were 
placed every 16 feet across the street and where car 
tracks occurred joints were placed 1 foot from the track 
on each side for the full length of the street. All joints 
were protected by the Baker armor plate. The price of 
the finished pavement was $1.22 per square yard, ex- 
clusive of excavation. The material and labor costs 
were as follows : 

Cement, per barrel $1.02 

Sand, per cubic yard f. o. b. the work 1.15 

Gravel, per cubic yard f. o. b. the work 1.15 

Common labor was $2.25 to $3.00 per day. 

The City of Rockville, Ind., constructed during 
1912 4,400 square yards of reinforced concrete pave- 
ment. This pavement was of a one-course instead 
of a two-course type. Although the use of a reinforce- 
ment necessitated placing the pavement in two layers, 
both layers consisted of the same concrete mixture, this 
being 1 part of Portland cement, 2 parts of sand and 
2% parts of gravel. The total thickness of the pave- 
ment was 5 inches and the reinforcement was triangle 
mesh No. 7, placed approximately in the center of the 
slab. The curb is 6 inches high and 5 inches thick, built 
directly upon the pavement and anchored to the same by 
means of steel loops placed every 5 feet. Expansion 
joints occur every 33 feet across the pavement and are 
protected by means of the Baker armor plate, the joints 
being filled with tar. Finished pavement cost $1.10 
per square yard, including excavation, and the material 
and labor costs were as follows : 



106 Concrete Roads and Pavements. 

Cement, per barrel $1.25 

Sand, per cubic yard 1.25 

Gravel, per cubic yard 1.25 

Common labor, per hour 20 

Very little excavation v^as required beyond surfac- 
ing to grade. The foundation consisted of a yellow clay 
v^hich required the depositing of a small amount of 
gravel in some places. The crov^n of the street v^as 4 
inches for a width of pavement of 26 feet. 

During the year 1912, Vinton, Iowa, laid 11,000 
square yards of a two-course reinforced concrete pave- 
ment of a total thickness of 7 inches. The 5-inch base 
course consisted of a mixture of 1 part Portland cement, 
3 parts of sand and 5 part of crushed stone. The 2-inch 
wearing course was mixed 1 part of cement to 2 parts 
of clean sharp sand. The reinforcement used was 
Triangle mesh N'o. 26, placed between the top and bot- 
tom courses over the center 16 feet of the pavement and 
was laid with the longitudinal wires at right angles to 
the center line of the street. Expansion joints were con- 
structed along curbs and across the street every 40 feet, 
these joints being protected with steel plates % of an 
inch thick and 2 inches wide, the same being anchored 
into the concrete by means of anchor bolts. The cost of 
the finished pavement, exclusive of excavation, was 
$1.07 per square yard, the costs of material and labor 
being as follows : 

Cement, per barrel $1.00 

Sand, per cubic yard for bauling 50 

Crushed stone, per cubic yard 1.30 

Common labor, per nine-hour day 2.25 ^ 

Connersville, Ind., contracted for the construction 
of 65,000 yards of reinforced concrete pavement during 
the year 1912 at a cost of $1.02 per square yard, includ- 
ing excavation. The base is 5 inches thick at the curbs 



Concrete Roads and Pavements. 107 

and 7 inches at the center and the top or wearing course 
is IV2 inches thick over the entire pavement. The con- 
crete for the base is mixed 1 part of Portland cement, 2 
parts of sand and 4 parts of crushed stone or gravel. 
The mixture for the wearing course is 1 part of cement 
to IV2 parts of clean sharp sand. The pavement is re- 
inforced with triangle mesh N^o. 7, placed between tne 
top and base courses. Expansion joints protected by 
means of Baker armor plate and filled with an asphalt 
filler are placed along the curbs and across the street 
every 30 feet. The material and labor costs were as 
follows : 

Cement, per barrel $1.02 

Sand, per cubic yard 50 

Gravel, per cubic yard 45 

All f. o. b. Connersville, Ind. 
Common labor, $2.00 per day. 

During 1912, Stanley, Wis., laid 9,000 square 
yards of reinforced concrete pavement having a total 
thickness of 6% inches. The 5 -inch base consisted of 1 
part Portland cement to 5 parts gravel and the 1%-inch 
wearing course consisted of 1 part of cement to 2 parts 
sand and granite screenings. The reinforcement used 
was triangle mesh ^0. 7 placed between the top and bot- 
tom courses. Expansion joints were placed along the 
curbs and across the street every 30 feet. IN'o steel pro- 
tection was used on the joints but the edges were 
rounded to a small radius to prevent chipping off under 
traffic. This pavement was laid at a cost of $1.52 per 
square yard, including excavation. 

The City of Mitchell, South Dakota, laid several 
blocks of reinforced concrete pavement during 1912, in 
accordance with plans and specifications furnished by 
S. H. Smith, city engineer. The base course was laid 



108 



Concrete Boads and Pavements. 



5% inclies thick and consisted of a concrete mixed in the 
proportion of 1 part of cement, 3 parts of sand and 5 
parts of crnshed stone. The sand was to be well graded 
and to contain no pieces larger than would pass a 'No. 4 
mesh screen. The crashed stone was graded in sizes 
ranging from % of an inch to 2 inches. On top of the 
base was placed triangle mesh No. 7 for a width of 20 
feet in the center of the pavement on Main street and 
15 feet on intersecting streets. The main longitudinal 
wires were placed crosswise of the pavement and the 
entire mesh was tamped into the freshly laid concrete. 
Over this was placed the wearing course 1% inches 
thick, consisting of 1 part of cement to 1% parts of a 
mixture of equal parts of sand and stone screenings. In 
order to give the finished pavement a dark color there 
was to be added % of a pound of lamp black to each 
sack of cement. The wearing course was properly 
floated to grade and troweled, and after becoming suf- 
ficiently hardened it was roughened with a street broom. 
Expansion joints % of an inch wide were placed along 
all curbs, and joints % of an inch wide were placed 
across the street every 25 feet, and around all catch 
basins or man-hole covers. The edges of all expansion 
joints were rounded to %-inch radius. After the pave- 
ment had taken sufficient set, the joints were filled with 
a suitable elastic waterproof compound. 

The Township of DeKalb, 111., constructed a short 
piece of reinforced concrete roadway pavement in 1912, 
the work being done under the supervision of A. N. 
Johnson, state engineer. The pavement consists of one- 
course work laid 6V2 inches thick, the concrete mixture 
being 1, 2 and 3. Expansion joints were constructed 
across the pavement every 50 feet and protected by the 



Concrete Roads and Pavements. 109 

Baker steel armor plate. Triangle mesh ISTo. 26 A was 
placed approximately in the center of the slab with the 
longitudinal wires at right angles to the center of the 
roadway. 

The City of Davenport, Iowa, laid during 1911 
several blocks of reinforced concrete pavement in which 
the reinforcement was placed near the bottom surface of 
the slab for structural reasons. The soil over which 
this pavement was to be laid consisted of refuse from 
saw mills, such as sawdust, chips, bark, etc., and was 
almost constantly saturated with river water. The 
street itself and the railroad track paralleling the same 
settled from eighteen to twenty-four inches every year. 
As the usual type of pavements could not possibly be 
expected to prove satisfactory with such a type of sub- 
soil (the pavement also being subjected to heavy and 
high speed traffic) it was decided to construct a concrete 
pavement reinforced with a sufficient amount of steel to 
produce a monolithic slab that would spread over a 
greater area any excessive loads coming upon the same 
under the traffic conditions. The pavement was laid 7 
inches thick of a 1 :3 :5 concrete mixture and reinforced 
with 0.5 per cent of triangle mesh reinforcement placed 
near the loAver surface of the pavement. The total cost 
for the work w^as $0.93 per square yard. 

Thomas Reinforcing for Pavements. This sys- 
tem of reinforcing is controlled by the Thomas Steel 
Reinforcement Company of Detroit, Mich. It is built 
up of %-inch rods, %-inch rods, spacing members 
called stools, and facing plates for the expansion joints. 
The %-inch round steel bars are placed longitudinally 
and crossways 2 feet center to center and 1 inch from 
the top surface of the finished concrete. The %-inch 



110 Concrete Roails and Pavements. 

round steel bars are placed longitudinally and cross- 
ways 4 feet center to center and 4 inches from the top 
surface of the finished concrete, and both systems are 
well clamped together at their intersections. The two 
systems are properly supported in their respective 
places before any concrete is laid, and in proper lengths 



^^/ff" ty^y-pag way JSm/- • 




Thomas Reinforcing for Pavement. 

and widths so as to be embodied in concrete panels 30 
feet long by the whole width of the road. The top and 
bottom bars are held firmly at intervals of 4 feet by 
an upright steel member, which will make a positively 
connected unit of the top and bottom bars through the 
whole pavement. 

Expansion joints %-inch wide are placed at right 
angles to the curb line at intervals of 30 feet. Joints 
have their edges protected by means of a soft steel 
plate 3-16 inch by 3 inch rolled to conform to the es- 
tablished crown of the pavement and the steel plates 
are securely attached to the reinforcing bars of the pave- 
ment so that the concrete between the expansion joints 
works as a unit. Expansion joints without steel plates 
are also placed along the side of the curb %-inch wide 
and the whole length of the paved street, the opening 
extending to the bottom of the concrete base and the 
space filled with asphalt filler. 



Concrete Roads and Pavements. Ill 

Generally the top bars are 2 feet center to center 
and those at the bottom 4 feet center to center, but this 
may vary according to climatic conditions. The ver- 
tical supports or stools are made of light angle iron 
sheared at the bottom so as to bend the feet, which give 
a bearing on the grade surface of the road. 

If expansion joints are used every 30 feet and the 
street is 24 feet wide, the fixity of these stools, which 
are generally placed 4 feet on centers, makes a large 
stone 24 feet wide by 30 feet long, composed of small 
stones 4 feet by 4 feet, without any joint between the 
small stones. 

This system requires about 50 tons of steel per 
mile of 24-foot pavement. The cost per yard is about 
5 cents for edge protectors, 22 cents for other steel, and 
3 cents for framing and placing. 



CHAPTER Yin. 

CoNCKETE IK Combination with Other Materials. 

Because of a lack of a suitable supply of sur- 
facing materials J or for other reasons, it may not 
always be desirable to construct the wearing surface of 
a road or pavement of concrete. But even when a top 
coat of some other material is desired, concrete can 
almost invariably be used to advantage as a base. For 
this purpose almost any local supply of stone or gravel 
can be used, and will give sufficient strength to carry 
the weight of traffic successfully, even though not 
adapted to come into direct contact with it. 

Used in this way, concrete has many of the advan- 
tages inherent in a complete concrete road or pavement. 
It forms an unyielding base of sufficient strength to 
bridge over imperfections or weaknesses in the sub- 
base, retaining its shape indefinitely and holding the 
wearing surface up to true grade and subject only to 
the wear on that surface itself; its monolithic nature 
keeps it secure from sinking into the soil ; and its dura- 
bility fits it to serve under an indefinite succession of 
wearing surfaces. It can be used to advantage as a 
base for any standard type of pavement, and would be 
put in approximately the same as the base for a two- 
course concrete pavement in the same location, except 
that expansion joints are not generally used. 

Mr. Robert Hoffman, chief engineer, Department 
of Public Service, Cleveland, Ohio', has made a con- 
siderable study of various bases for brick pavements 

112 



Concrete Roads and Pavements. 113 

and gave the result of his investigations before the 
American Association for the Advancement of Science. 
He said : 

''That an unyielding sub-base, such as concrete 
affords, is highly desirable goes without question, and 
it should be supplied wherever possible, and in most 
cases will prove more satisfactory, even at slightly 
greater cost. Concrete will carry the pavement load 
over the many soft places caused by street openings 
prior to paving and will prove a factor of safety 
against settlements and irregularities liable to occur 
where no concrete is employed. Any settlement in a 
pavement foundation breaks the bond of the brick and 
will be rapidly followed by serious deteriorations. 

''Another possible economy in supplying a concrete 
foundation may be found in the possibility that some 
time it may be desired to replace brick with other kinds 
of paving material for which a concrete foundation 
must be supplied, such as wood block, asphalt or as- 
phaltic concrete, in which event the cost will be mate- 
rially lessened by reason of the existing concrete. 

"In open country with poor drainage facilities, 
there is no doubt that the drainage effect of frost and 
the yielding sub-soil would soon depreciate any brick 
pavement with only a natural soil foundation, and there 
concrete is the only safe and economical foundation." 

A bituminous surface is considered of advantage 
by many builders of concrete pavements, for taking 
the wear, giving a certain amount of resiliency, and 
giving greater freedom from noise. Mr. Logan Waller 
Page has also pointed out that such a surface ought to 
be of undoubted value, if put on soon after the con- 
crete is placed, because of the fact that it will help to 




(lU) 



Concrete Roads and Pavements. 115 

retain the original moisture in the concrete, thus allow- 
ing it to attain the fullest possible strength. 

The application of such a coating is mentioned in 
connection with a number of jobs described in this 
volume. Descriptions of varioi'is patented types of 
such pavements are also given in Chapter IX, and 
specifications are given in the Appendix. 

In some instances an excellent concrete base has 
been made economically by installing a crusher oh the 
job and crushing the stone from an old granite block 
pavement. 

Cement grout is also coming to be recognized as 
the best filler for brick and stone block wearing sur- 
face. Some surprising comparisons have recently been 
made of brick pavements with cement filler and those 
with ordinary sand, showing the latter with joints 
empty and edges rounded in a comparatively short 
time, while the grouted joints show little perceptible 
wear after a number of years. 




Crushing: Old Stone Blocks for Concrete Base. 



116 Concrete Roads and Pavements. 

The E^ational Paving Brick Association advocates 
strongly the use of cement grout filler for brick pave- 
ment, as well as a concrete base. Speaking before the 
Association of Portland Cement Manufacturers, Mr. 
Will P. Blair, secretary of the National Paving Brick 
Association, said: 

^^In the use of a cement filler, the important ele- 
ment of ease of traction is greatly assisted. By it a 
monolithic surface is formed, while the brick protects 
the thin portion or joint of cement, insuring a uniform 
wear upon the whole surface. In the earlier use of such 
a street the slight unevenness of the brick, which will 
obtain for the first few years, according to the amount 
of trafiic upon the street, will prevent slipping and 
skidding which otherwise might occur owing to the film 
of glaze that is always present upon every No. 1 paving 
brick. As this glazed film in time disappears, the road- 
way becomes smoother, the granular surface follows, 
which for ease of traction is not found with any other 
form of pavement whatsoever, and is never approached 
in the case of a brick or stone pavement constructed 
with any other filler. 

"The hardened joints of the cement filler are sufii- 
ciently rough and will stand the shock from the impact 
so that it will not shatter. With the relief afforded by 
the uniform two-inch compressed sand cushion, required 
as a necessary adjunct in the transmission of the load 
to the monolithic wearing plate, this joint is not broken. 
The vibrations of the impact upon the wearing plate are 
distributed without injury and the load is not concen- 
trated wholly upon any individual brick. With the 
monolithic plate resting upon the uniform cushion sup- 
port, the cushion itself is not affected or disturbed 



Concrete Roads and Pavements. IIY 

except to the minutest extent, whereas, in the use of 
the soft filler, a continuous maximum disturbance oc- 
curs, the brick being subject to a constant displacement. 
Their support cannot be uniformly maintained, hence 
the surface is divided into as many planes as there are 
bricks in the street. 

"The force of the entire weight where the soft 
fillers are used is directed to the single brick as the 
wheel comes in contact with the same. The brick do 
not chip where the cement filler is used. They do chip 
where the soft fillers are used. The street grows better 
as it grows older, and the smoother it wears, the less 
slippery it becomes. Of course this does not hold good 
indefinitely, but it does hold good for an undetermined 
number of years. It is certain with the use of soft 
fillers, chipping at the corners and edges of the bricks 
immediately follows the use of the streets. In case 
of granite there results a smooth, rounded condition 
of the stone, subjecting the horses to most cruel and 
incessant short slipping, impairing their value and 
shortening their lives. 

"The wear on the cement filled streets is scarcely 
perceptible from year to year. It is slight and level, 
and in continued harmony with the grade of the street. 
'^0 waves or depressions are produced. Hence the im- 
pact is always at a minimum, and it follows the wear 
must be likewise so." 

The following directions for the application of 
cement grout filler are recommended by the J^ational 
Paving Brick Association: 

"The filler shall be composed of 1 part each 
of clean, sharp, fine sand and Portland cement. The 
sand should be dry. The mixture, not exceeding 1 



118 Concrete Roads and Pavements. 

sack of the cement, together with a like amount of 
sand, shall be placed in the box and mixed dry, until 
the mass assumes an even and unbroken shade. Water 
shall then be added, forming a liquid mixture of the 
consistency of thin cream. 

^^The sides and edges of the brick should be thor- 
oughly wet by sprinkling before the filler is applied. 

^Trom the time the water is applied until the last 
drip is removed and floated into the joints of the brick 
pavement, the mixture must be kept in constant motion. 

^'The mixture shall be removed from the box to 
the street surface with a scoop shovel, all the while be- 
ing stirred in the box, as the same is being thus emptied. 
The box for this purpose shall be 4 feet, 8 inches long, 
30 inches wide and 14 inches deep, resting on legs of 
different lengths, so that the mixture will readily flow 
to the lower corner of the box, which shall not be more 
than 6 inches above the pavement. This mixture, from 
the moment it touches the brick, shall be thoroughly 
swept into the joints. 

^^Two such boxes shall be provided in case the 
street is 20 feet or less in width; exceeding 20 feet in 
width, 3 boxes should be used. 

^^The work of filling should be carried forward in 
line until an advance of 15 to 20 yards has been made, 
when the same force and appliance shall be turned back 
and cover the same space in like manner, except that 
the mixture shall be slightly thicker for the second 
coat. 

''To avoid the possibility of thickening at any 
point, the surface ahead of the sweepers and ahead of 
the mixture shall be gently sprinkled, using a sprink- 



Concrete Roads and Pavements. 119 

ling-can, the Lead of Avliicli sliall be perforated with 
small holes. 

^^Any attempt to thin the mixture on the pave- 
ment by the application of water will result in the 
separation of sand and cement, and 'bad spots' will ap- 
pear in the pavement where this practice has been per- 
mitted. 

''After the joints are thus filled flush with the top 
of the brick, and suflicient time for hardening has 
elapsed, so that the coating of sand will not absorb any 
moisture from the cement mixture, % inch of sand 
shall be spread over the whole surface ; and in case the 
work is subjected to a hot summer sun, an occasional 
sprinkling, suflicient to dampen the sand, should be 
followed for two or three days." 

Louisville, Ky., has been an advocate of and a 
builder of brick streets for years. It is located near 
some first-class brick plants and the relative ease of 
getting the material, as well as other considerations, 
led to many miles of street of this type being con- 
structed. Sand filler was used exclusively. The results 
were extremely unsatisfactory. Instead of lasting ten, 
twenty or tAventy-five years, as it is claimed that brick 
will do under proper conditions, the work went to 
pieces in a few years, and irregularities, gradually 
developing into large holes, made their appearance 
almost immediately after use was begun. It is con- 
ceded that a large part of the defects were due to the 
use of i^oor paving block, but it is also believed that the 
character of the filler was responsible for the chief 
trouble. 

In 1909 the municipality decided to face about on 
the grouting proposition, and specified that cement 







120 



Concrete Roads and Pavements. 121 

filler be used. The first year that the work was done 
under these specifications fair results were obtained; 
but since then, as inspectors and contractors both have 
become accustomed to the method, and know exactly 
how the filler should be applied, really magnificent 
streets have been built. There are some stretches of 
brick streets in Louisville, laid in cement grouting, 
that are pronounced by experts to be the equal of any 
in the United States. Certainly they are free from 
irregularities, absolutely smooth, are wearing down uni- 
formly and have joints which give not the slightest 
indication of opening up or permitting the street to 
disintegTate. 

Another big disadvantage of the sand filler is seen 
in connection with the use of luodern street cleaning 
methods. Flushers which throw out water with con- 
siderable force tear the grouting out of a street on 
which a soft filler is used and leave it in a deplorable 
condition. In the case of cement, of course, the action 
of the water is not at all harmful, and street flushing 
machines may be used without question. 

The success of the cement grouting system has 
been so great with reference to brick streets that the 
Board of Public Works of Louisville has extended it 
to granite streets. In this case, the joint, instead of 
being from % inch to % inch in thickness, as in brick 
streets, is from % inch to 1 inch thick. The blocks are 
rammed instead of rolled and a little gravel is swept 
into the joints to hold the blocks steady while they are 
being rammed. 

The following suggestions for grouting granite 
blocks were given by Mr. William A. Howell in a paper 



122 'Concrete Roads and Pavements. 

before the American Society for Municipal Improve- 
ments : 

1. Be sure your sub-grade is well rolled, and all 
soft places eliminated. The concrete should not be too 
rough and should be laid' to a true crown. A uniform 
thickness of two inches of sand bed under the blocks 
should be maintained. 

2. The blocks, after careful culling, should be 
well rammed. 

3. • Be absolutely sure the cement is good and the 
sand is clear and sharp. A small percentage of clay, 
not over 5 per cent, is preferable to act as a binder. 

4. Great precautions should be taken to have the 
correct proportions of sand and cement in the mixture. 

5. Keep the mixture continually agitated in the 
box; always remove the ground mixture from the box 
with scoop shovels. The contents of the box should 
never be dumped on the street; wherever this is done 
there is always a bare spot in the grouting. 

6. The blocks should be thoroughly wet by sprink- 
ling immediately before grouting. 

Y. Grouting should not be attempted during cold 
or frosty weather. Good results are seldom secured 
after JSTovember 15th in the latitude of E'ew York city. 

8. If the grouting is done during very hot 
weather, it should be immediately covered with a half- 
inch coating of sand which should be kept constantly 
moist by frequent sprinkling during the continuation 
of the hot spell. 

9. Traffic should be kept away from the grouted 
pavement for at least seven days. 

10. If the best results are desired with a mini- 
mum amount of effort, the use of a moderately soft 



Concrete Roads and Pavements. 123 

granite, similar to N^ew Hampshire granite, is recom- 
mended. 

Experience at Appleton, ^yis. Concrete pave- 
ments with bituminous wearing surface have been used 
for the past four years in Appleton, Wis., with very 
good results, according to C. H. Yinal, the city en- 
gineer. The specifications provide for a sub-foundation 
of 2 inches of sand and cinders mixed one to one and 
thoroughly rolled or tamped, the sub-grade having pre- 
viously been rolled. Upon this base a 5-inch concrete 
foundation was laid, mixed 1 :3 :6. This was provided 
with expansion joints along each curb, around all man- 
holes or other fixtures, down the center of the street if 
this should be more than 28 feet wide, and crosswise of 
the street every 40 feet; these expansion joints being 
from % inch to 1 inch in width. The edges of the 
transverse expansion joints are protected with 2^/2x2%- 
inch steel angle irons, rolled with a corrugated or dia- 
mond surface to prevent being slippery; these angle 
irons being set so that their upper surfaces come flush 
with the wearing surface, and anchored to the concrete 
with anchor bolts. The joints extend the full depth of 
the concrete foundation and are completely filled from 
the bottom to within a half inch of the top of the fin- 
ished pavement with asphalt poured into the joints at a 
temperature not lower than 300 degrees. 

After the concrete base has been placed and before 
it has begun to set, a 1%-inch wearing surface is placed, 
which is composed of 1 part Portland cement to 1% 
parts of crushed rock, from which all dust has been 
removed ; the crushed rock consisting of approximately 
40 per cent of ^A-inch size, 20 per cent of %-inch size 
and 15 per cent of iV-inch size, the balance of about 



124 Concrete Roads and Pavements. 

25 per cent being sand. The exact proportion of these 
materials, however, may be varied by the engineer in 
order to obtain as dense a mixture as possible. Crushed 
stone and cement are mixed dry and then wet to the 
proper consistency, deposited on the concrete and 
worked or floated to a uniform surface which it is speci- 
fied shall be free from waves or honeycombs. The sur- 
face is then treated by drawing a tool similar to a 
garden rake both crosswise and lengthwise of the street 
so as to cut the surface into squares of 2% inches on a 
side, the cuttings being about % inch deep. 

The paving is then allowed to dry, when the entire 
surface is covered with a coat of asphaltic cement, 
heated to a temperature of not less than 300 degrees and 
poured or spread over the surface to a depth of about 
one-eighth of an inch, mops, brooms or squeegees being 
used for this purpose. On this is spread evenly a 
dressing of fine stone chips heated to at least 250 de- 
grees, enough being used to cover the entire surface. 
When the asphalt is cold the road is ready for traffic, 
which rapidly wears in or wears away the chips. 



CHAPTER IX. 

Patented Conckete Pavements. 

There are on the market and in successful use a 
number of patented concrete pavements, the patents 
covering either the combination of materials, the 
method of combining them, or the equipment by which 
the work is done. These pavements are described in 
this chapter, and specifications for them are given in 
the Appendix. 

Granitoid and Granocrete. These two types of 
pavement are patented under patents owned by the Ru- 
dolph S. Blome Company, City Hall Square Building, 
Chicago. They are both two-course pavements, in each 
of which a special feature is the scientifically correct 
proportioning and grading of the materials, especially 
in the surface, so that they will withstand the greatest 
amount of wear. 

By reference to the specifications for Granitoid 
and Granocrete pavements in the Appendix the careful 
manner in which the combination of the concrete has 
been adjusted to the wear will be at once apparent. It 
will be noticed that while a liberal amount of cement 
is used, it is used as a binder only, allowing the wear 
of traffic to come upon the carefully graded hard aggre- 
gate of which the surface is composed. This not only 
makes for the long life of the pavement, but also keeps 
it from becoming slippery with wear. 

Of the two types Granitoid has the thicker and 
stronger top coat, and is intended for the heavier traffic, 

125 




(126) 



Concrete Roads and Pavements. 127 

while Granocrete is designed mainly for residence 
streets, country roads and other districts of lighter 
wear. 

The distinctive featnre of Granitoid pavement is 
that it has the snrface cut into blocks of abont 4i/2x9 
inches in size, with rectangular surfaces similar to pav- 
ing blocks. This surfacing is done by a special method 
and apparatus covered by the Blome patents. Grano- 
crete has an approximately smooth surface without 
markings. 

Both forms of pavement have expansion joints at 
suitable intervals filled with a special composition cov- 
ered by the patents. 

Bitustone. This is the title given to a form of 
concrete pavement patented by Warren Brothers Com- 
pany, Boston, Mass. It is described in detail by Mr. 
August E. Schutte in Good Roads Magazine, as fol- 
lows : 

''The Bitustone pavement is a pavement in which 
advantage is taken of the hardening of the Portland 
cement and of its rigid structure, when combined with 
the elastic and silencing effect of bitumen. Each indi- 
vidual particle of stone is held first by the Portland 
cement and then again by the bituminous cement. In 
constructing, there is first laid the bottom course, w^hich 
is an ordinary concrete, preferably of the proportions 
of 1 :3 :6. Upon this bottom course is then laid a 1%- 
inch layer of practically uniform sized stone, coated 
with neat Portland cement in such a manner as to 
produce a bonding and keying effect between the indi- 
vidual stones, and a cementing effect at the points of 
contact, due to the Portland cement. This is easily 
produced by coating the stone in proportions of about 



128 



Concrete Roads and Pavements. 




SECTIONAL VIEW OF BITUSTONE PAVEMENT 

The light colored coating surrounding the stone marked "A" is the 
Portland Cement; dark filler between the stone is the bituminous com- 
pound, marked "B," and the coating of stone chips producing a rough 
surface is marked "C." 



six parts of stone to one of Portland cement. The ce- 
ment must not be so wet as to separate from the stone 
and run to the bottom, but must be of about ^medium 
consistency/ so that each stone will be thoroughly 
coated with neat Portland cement mortar, and when 
placed a double coating will be between each tw^o stones 
at the exact point of contact. In that way is produced 
about an inch and a half of a course which I prefer 
to call the bonding course, for it serves to bond the bi- 
tuminous cement to the stone, prevents its displacement, 
provides a surface coating of bitumen which is thor- 
oughly keyed into the concrete bonding layer, and 
produces resiliency and durability by avoiding all abra- 
sions and breaking loose of the aggregate forming the 



Concrete Roads and Pavements. 129 

bonding course. It is understood that this bonding 
course forms a reticulated, nicsh-like, vesicular, porous 
structure, into which the hot bitumen, which is poured 
upon and into this layer, enters, and adhering to the 
Portland cement, holds the particles of stone by its 
adhesion and cohesion. Thus there is produced in this 
pavement a combination of the entire strength and ri- 
gidity that can be obtained from Portland cement, 
combined with the strength, non-slipperiness and re- 
sistance to abrasion of the best bituminous macadam, 
and at the same time there is produced a pavement in 
which the wearing surface and foundation are one, 
which is rigid, and which can be laid on any sort of 
foimdation without any special preparation. 

^'The main advantage of this pavement is its ina- 
bility to be shoved and displaced. With its ^fool- 
proofness' and possibility of being laid with unskilled 
labor, and with practically no machinery, barring per- 
haps a concrete mixer and ordinary bitumen kettle, the 
advantage can be particularly appreciated by those who 
have attempted to lay country roads with complicated 
machinery, with its attending delays on account of 
break-downs, lack of fuel, water, etc." 

Dolaway Pavement. The patents on this pave- 
ment are controlled by the Dolarway Paving Company, 
Whitehall Building, ^e^Y York. 

This pavement was first used at Ann Arbor, ^lich., 
in 1909, with 1,883 square yards laid, followed by 
18,000 yards in 1910 and 64,000 in 1911, and in the 
spring of 1912 there were petitions on file for 140,000 
additional square yards. This pavement is practically 
a concrete pavement covered with a bituminous mate- 




130 



Concrete Roads and Pavements. 



131 



rial. The requirements for the concrete at Ann Arbor 
are somewhat imique, as quoted herewith : 

"One standard sack of cement shall be used for 
each square yard of pavement, and upon the completion 
of the pavement, if it shall be shown that less cement 
has been used than specified, the value thereof shall be 
deducted from any money due the contractor, and the 
contractor shall furnish to the Board of Public Works 




Section Cut from Dolarway Pavement. 



132 Concrete Roads and Pavements. 

a sworn statement of the total quantity of cement used. 
Within 30 minutes after the concrete is placed it shall 
be struck off with a templet approved by the engineer 
until flush with the running boards, and as soon there- 
after as practicable be trowelled to a true surface and 
be broomed as directed. An expansion joint 1 inch 
wide shall be left at each curb, and an expansion joint 
about 1-2 inch wdde shall be left every 25 feet trans- 
versely of the street." 

After the concrete has become thoroughly set and 
dry a thin coating of Dolarway bitumen, about 1-2 
gallon per square yard, is applied at a temperature of 
about 200 degrees F., and before the bitumen applied 
has become hard there is spread over the entire surface 
a uniform layer of torpedo sand, the transverse joints 
being filled with the bitumen and sand flush with the 
surface of the pavement. The thickness of the bitu- 
men and sand ranges from 1-4 to 3-8 of an inch. It is 
claimed for this pavement that the concrete serves 
really as the pavement, and that the surface coating 
of bitumen and sand protects the concrete from wear, 
so preventing the formation of dust and giving prac- 
tically an asphalt pavement so far as use is concerned. 

The cost of the pavement varies, of course, ac- 
cording to localities and the cost of materials, but it is 
stated that if there be added to the cost of concrete 
25 to 35 cents per square yard, the same being the cost 
of the bitumen and the royalty charged by the company, 
the total cost of the pavement can be obtained. It is 
stated also that the pavement can be resurfaced at an 
approximate cost of 10 cents per square yard. 

Hassam Pavement. The following description of 
the Hassam pavement is furnished by Mr. Harold 



Concrete Roads and Pavements. 133 

Parker, vice-president of the Hassam Paving Com- 
pany, Worcester, !Mass. : 

^'The so-called Ilassam pavement is in its present 
form the perfected result of many experiments made 
by W. S. Hassam while he Avas superintendent of streets 
of Worcester, ^Mass., and since, after it was found that 
the method put into practice by him as an official had 
a large commercial value. Tt was found in practice that 
ordinary mixed concrete used as a foundation for brick 
or stone block pavements failed to meet all the require- 
ments. Tt was found, for example, that it was difficult 
to obtain a perfectly uniform surface on which to place 
brick or stone blocks and have it at the same time of 
uniform density or with a uniform distribution of in- 
gredients. 

^When the concrete is laid for foundations of piers 
or buildings and the mass is of great depth, this fact 
is not of great importance ; but when only a thin layer 
on the sub-grade of a road or street is required, it be- 
came of serious moment. It will be recognized that 
owing to the different specific graA'ity of the various ma- 
terials composing the concrete mass, there will be a sepa- 
ration of the parts before the cement is set. This is 
practically observed when a batch of concrete is trans- 
ported either in a wheelbarrow or cart; the shaking of 
the mass, even when run over a good roadway or plank, 
settles the mineral aggregate to the bottom and leaves 
the cement mortar on top. The dumping of a barrow 
or cart-load still further disturbs the relation between 
them. Each load that is dumped is more or less differ- 
ent from all others and there is greater density in some 
portions of each load than in other portions, so that as 
a matter of fact it will be found on examination of 



134 Concrete Roads and Pavements. 

concrete laid on the sub-grade of a road or street that 
masses of stone with comparatively small amounts of 
cement and sand will result, and in others cement and 
sand and very little rock; in short, no two adjoining 
sections will have the same amount of the specified in- 
gredients. This condition is but little helped by ram- 




Section of Hassam Pavement. 



Concrete Roads and Pavements. 135 

iiiing or tamping. The practical result is that two un- 
satisfactory conditions are manifest, viz. : that the sur- 
fact of the cement foundation is uneven, and the sus- 
taining strength of the concrete is never the same in 
all parts of the road. 

^ 'These conditions led to a series of experiments in 
order to obtain for stone block, brick or wood block pave- 
ment an even foundation of uniform strength, which 
would secure a smooth final surface and one which would 
hold its shape indefinitely. It was found after many 
trials that the most satisfactory, if not, indeed, the only 
way to obtain all the necessary characteristics for such 
a base was as follows: Broken stone sufficiently tough 
to withstand the weight of a 10-ton roller w^hen run 
over it enough to thoroughly compact it, is placed upon 
a properly prepared sub-grade and rolled until thor- 
oughly compacted. This stone should be of cubical 
form and not less than 2 inches in its largest dimen- 
sions, and should be so carefully placed that after roll- 
ing it should present a perfectly uniform cross-section, 
rough because of the large size of the individual stones, 
but uniform in shape both longitudinally and laterally. 
The voids between the stones are then reduced to a 
minimum, and a cement grout composed of 1 part 
hydraulic cement to 2 or more parts of sand and suf- 
ficient w^ater to secure an easy flow, is then distributed 
evenly over the stone placed as above described. This 
can best be done by a grouting machine invented for the 
purpose. 

"Before the grout has begun to set the whole is 
thoroughly rolled again. This is done to force the grout 
into every void and to drive out any air, making the 
whole a monolith. This process compresses the concrete 




(136) 



Concrete Roads and Pavements. 137 

from 15 to 25 per cent compared to ordinary mixed and 
tamped concrete; in other words, the same amount of 
material will occnpy from 15 to 25 per cent less space; 
moreover, every square yard of surface Avill have exactly 
the same amount of stone under it, with an exactly uni- 
form amount of cement and sand. Any pavement laid 
in such a foundation never gets out of surface, except 
by the wearing away of the surface itself; depressions 
in the road never appear by reason of settlement or 
lack of uniformity of the foundation — all parts are 
of equal strength. 

^^The foundation laid as I have described was 
found to be so uniform in shape and so indestructible in 
character that where traffic was not too severe, it was 
adopted as a completed road and many hundreds of 
thousands of yards have been so laid with entire satis- 
faction, the only criticism possible being that surface 
cracks appear unless great care is taken to protect the 
top until well set. Such cracks do not reduce the 
strength of the road, but they are unsightly and some- 
times chip on the edges. So-called expansion joints 
will not prevent the occurrence of such cracks, because 
the cracks are the result of contraction and not expan- 
sion. This is the difference between the foundation I 
have described and the same method used as a finished 
road, viz. : that the distribution of the grout should be 
so made that the actual wear of wheels and horses' feet 
should come upon the stone and not on the grout. This 
can be done by brushing with wire or other coarse broom 
before the cement is set, the brushing to be done from 
side to side and not longitudinally. A smoother top can 
be obtained, of course, by flushing the surface with a 
richer grout. 



138 Concrete Roads and Pavements. 

^'A road built in this way is, of course, somewhat 
dusty, and more or less noisy; it is also rigid and hard 
on horses' feet, but not slippery. In order to overcomb 
these objections, experiments were made in using tar 
or other bituminous compound to cover the surface. 
These experiments began as long ago as 1906 with ordi- 
nary gas house tar, put on with pails and brooms. It 
was found that this tar so applied stripped off and at 
the end of a year of fairly heavy and varied traffic most 
of it had disappeared. Since then many trials have 
been made, and, as a result, my own view is that the fol- 
lowing produces the best road surface. The concrete 
road made as I have outlined must be thoroughly 
cleaned, washed if possible so that no dirt or foreign 
matter remains in it. While the surface is still slightly 
damp a coal gas or water gas tar, refined, but with some 
of the volatile oils still remaining, should be applied 
to the surface by means of a machine that will force 
it onto the road under pressure of 70 to 80 pounds to 
the square inch with the nozzles of the machine within 
six inches of the road. This application should not 
exceed % gallon to the square yard. Immediately after 
this application is made it should be evenly covered with 
stone chips and rolled with a light steam roller. After 
brooming off the loose chips another application of 
heavier tar, or preferably asphalt, also under pressure, 
and a little more in quantity (from % to % gallon), 
this layer also to be immediately covered with stone 
chips or coarse sand, and again rolled." 



CHAPTEK X. 

The Theory ais^d Practice oe Joints. 

xllmost all concrete roads and pavements are pro- 
vided with joints at regular intervals, nsually termed 
expansion joints, though this term is probably a mis- 
nomer. The joints are in fact provided to take care of 
contraction rather than expansion, as the concrete is at 
its greatest bulk when first placed under ordinary tem- 
perature conditions, an increase in temperature of 
nearly 100 degTees being required to expand it to its 
original bulk after it has once contracted to its normal 
volume. 

These joints, then, are simply provided to bring 
cracks, which would otherwise occur irregularly, at cer- 
tain definite points in order that they may be more 
carefully taken care of and protected. 

The theory on which expansion joints are deter- 
mined was given by Mr. A. IN". Johnson, State High- 
way Engineer of Illinois, before the Highway Con- 
gress in Atlantic City in 1912. His statement is as 
follows : 

"Owing to the constant movement of a concrete 
pavement due to temperature changes, it is impossible 
to prevent cracks forming. On hot days the pavement 
tends to lengthen, and on cool days to shorten. It is 
evident that the cracks form when the pavement tends 
to shorten. As the pavement moves over the sub-soil, 
there is developed a frictional resistance which in- 
creases foot by foot as added length is given to the 
section under consideration. 

139 



140 Concrete Roads and Pavements. 

"In a section of pavement of indefinite length, as 
it tends to shorten under the action of low temperature, 
a length of the pavement will be pulled over the sub- 
soil, on which the frictional resistance to be overcome 
just equals the tensile strength of the concrete. When 
such a point is reached the pavement cracks ; thus we 
can conceive that a section of pavement between two 
such cracks did not move at the center, but tended to 
draw towards the center from the ends where the cracks 
occurred, and that therefore this length of pavement, 
whatever it may be, represents a section twice as long 
as the strength of the pavement or tensile strength of 
the concrete would permit to be dragged over the sub- 
soil or earth foundation. 

^^If we are to forestall the formation of cracks 
in a haphazard way, it will be necessary, then, to pro- 
vide joints close enough together that there will be 
sufficient strength in the concrete to drag one-half its 
length between joints. 

^'If expansion joints are placed from 40 to 50 feet 
apart, and on the assumption that the coefficient of fric- 
tion of the pavement with the sub-soil is one, the ten- 
sile strength to be exerted as the pavement shortens 
under low temperature will be 20 to 25 pounds per 
square inch. 

^The advantage of making the cracks beforehand 
is that their edges may be properly protected from 
traffic. It will be realized at the outset that the ex- 
pansion joints constitute the weak points in the pave- 
ments, and that there should be as few of" them as 
possible. 

^^It has been suggested that as concrete sets it 
shrinks an amount about equal to the expansion due to 



Concrete Roads and Pavements. 141 

TO or 80 degrees temperature change^ so that it will 
be necessary to allow only for arbitrarily weak sections ; 
for instance, a paper joint placed every 50 or 100 feet. 
As a pavement sets it will shrink and make a sufficient 
opening to allow for subsequent expansion. 

^^If the joints become filled with a rigid material, 
the change in length due to ordinary variation in tem- 
perature will result in the development of compressive 
stresses of about 1,000 pounds per square inch. The de- 
formation that will be produced in the concrete for such 
stress would about equal the temperature deformation. 
But a thin slab of concrete of definite length and sub- 
jected to compressive stresses of 1,000 pounds per 
square inch must necessarily buckle. 

^'If a concrete pavement is laid Avithout expansion 
joints it might pass the first season without any serious 
consequences from buckling, as the cracks that are 
formed by the low temperature might not become suf- 
ficiently filled with incompressible material but that 
they would afford some relief as the pavement ex- 
panded under subsequent temperature rise." 

The distance apart at which these joints should be 
made has never been worked out definitely, but will 
vary, of course, with the nature of materials and the 
nature of the sub-soil. A distance of 25 to 30 feet 
seems to have been arbitrarily adopted in most cases, 
however, and is on the safe side. As this kind of con- 
struction progresses it will probably be discovered that 
joints can be placed farther apart, possibly up to 50 
feet. 

Mr. Johnson, who is quoted above, recommends 
that joints be placed at an angle of 60 degrees with 
the center line of the road and that alternate joints 



142 Concrete Roads and Pavements. 

be made parallel, swinging first one joint 60 degrees in 
one direction and the succeeding joint 60 degrees in 
the other. His idea is that placing the joints at an 
angle will tend to make the irregularity less notice- 
able as the wheels of vehicles pass over them, while 
the placing of succeeding joints in opposite directions 
he believes will tend to reduce any cumulative vibra- 
tions. 

As a matter of fact, however, joints in roads and 
pavements are rarely made in any way except at right 
angles to the center line. The reason for this is prob- 
ably that this method of construction is somewhat 
easier and more economical; and at the same time an 
effort is usually made to have the joints so thoroughly 
protected that they will not be noticed by traffic passing 
over them. 

There are a number of different methods of mak- 
ing joints in these pavements, the most simple but 
probably the least to be recommended, being that of 
placing a board in the joint, this board being from 5-8 
to % inch thick and cut to the shape of the finished 
roadway above and the sub-grade below. This board 
is held in place by stakes until after the concrete is 
placed ahead of it, when the stakes are removed, the 
board being left in place. This kind of a joint is ob- 
jectionable because of the fact that the board will ab- 
sorb a large amount of moisture and will expand; if 
the concrete has not sufficiently contracted to allow this 
expansion taking a lateral direction the board will ex- 
pand upward, making a ridge in the road. This board, 
too, will wear out much faster than the concrete, allow- 
ing the traffic to hammer the edges of the concrete, 



Concrete Roads and Pavements. 143 

eventually making a joint which will require consid- 
erable attention to keep it in shape. 

Another form of joint contemplates the use of a 
similar board, but with the difference that the board 
is taken out after the concrete has had its initial set 
and the joint is later filled with some kind of asphaltic 
preparation. 

A much better joint is made by the use of a simi- 
lar board, to which is tied one or two thicknesses of 
asphaltic felt. When the joint is placed it is set with 
the felt toward the completed work and the concrete 
is then poured in against it. As soon as the next sec- 
tion is started and sufficient concrete poured in against 
the other side of the board to hold it in place the strings 
are cut and the board is removed, allowing the concrete 
to flow up against the felt. This makes a narrow joint, 
but sufficiently wide for all practical purposes, and is 
perhaps the best joint in use except the steel protected 
joint, of which there are two or three types in use. 

Baher Armor Plate. This joint is made by the 
R. D. Baker Company, Detroit, Mich., and consists 
of a 3-16 inch soft steel plate 2% inches wide and 
curved to the crown of the road. This plate has shear 
members cut at regular intervals, these being bent out 
when the joints are placed, and serving to anchor the 
joints firmly to the concrete. Two of these armor plates 
are used at each joint, with one or two sheets of as- 
phalt between them, the felt running to the full depth 
of the concrete slab. 

These joints are assembled in a device known as 
an installation bar, this being a "T'' beam somewhat 
longer than the width of the roadway, and curved to its 
crown. The two plates and felt between them are as- 



144 



Concrete Roads and Pavements. 



sembled on this bar and locked into position by a lock- 
ing device which the bar carries. The ends of the in- 
stallation bar are then placed on the side rails of the 
roadway in the case of a country road, or auxiliary 




m 

.^•A^ 



\ 


\ 

V 




\ 


1 










/ 




/ 



Baker Armored Joints. 



handles to the bar are allowed to rest on the curb in 
case of a city pavement. 

These plates are made of steel which is tempered 
in such a way that it will take about the same rate of 
wear as concrete. It, therefore, continues to protect 
the edge of the joints during the entire life of the 
roadway. 

Trus-Con Armor Plate. This is a joint protector 
which has been developed by the Trussed Concrete 
Steel Company, Detroit, Mich., and is made of high- 
grade open hearth steel plate, and designed to wear 
with the rest of the pavement, providing at all times a 
smooth, even surface without rocks or bumps. Each 
plate is 2^/2 inches wide and 3-16 inches thick, and 
is made in lengths to suit. The plates are curved to 
the contour of the pavement. 

Tongues are sheared from the plate at frequent 
intervals, and these tongues again sheared at the end, 
the two prongs thus formed being bent in opposite di- 



Concrete Roads and Pavements. 145 

rcctioii, so that the phate is firiiily anchored to the con- 
crete. 

Two of these bars are chimped together Avith a 
layer of asphaltum felt between them, or, if preferred, 
a steel plate is placed temporarily between these armor 
plates, and the joint is afterward filled with plastic 
asphaltum. 

^lorseAYarren Joint. This joint is made by the 
Morse-Warren Engineering Company, Carlinville, 111. 
It consists of a T-shaped soft metal bar, the head of 
which spans the space between the sections of concrete, 
while the stem is interposed between the confronting 
edges of snch sections. Compressible strips are placed 
each side of the stem, and the stem near its lower edge 
has Ings stamped out to form a bond with the concrete. 

Ronghly speaking, the nse of metal plates for 
joints adds abont 5 cents per sqnare yard to the cost of 
the roadwav. 



CHAPTER XI. 

Some Tests of Concrete as a Roadway Material. 

Tlie most valuable tests of road materials which 
have recently been made have been those carried on by 
the Department of Public Works of the City of De- 
troit. The value of these tests consists in the fact that 
they were made with actual sections of pavement under 
an approximate duplication of traffic conditions rather 
than being mere arbitrary tests of materials. 

For the purpose of these tests a device called a 
paving determinator was made by Mr. J. C. McCabe, 
city boiler inspector of Detroit. This device runs over 
a circular track, and in the original test this was com- 
posed of eight different sections of pavement. 

The whole track was underlaid with 8 inches of 
concrete, the foundation for all experimental pave- 
ments. The block pavements were put down under 
Detroit specifications. All the block and brick were 
cushioned on 2 inches of sand, which had previously 
been thoroughly compacted with hand tamps. The 
spaces between the cedar block were filled in with 
gravel, and the brick and granite were well grouted. 
The concrete was laid 6 inches thick of a mixture of 
1 :1% ::3, using washed sand and pebbles, according 
to the Wayne county specifications. The samples were 
not disturbed for 60 days, when the test was begun. 
This test showed the concrete section to have by far 
the greater resistance to wear. 

The determinator consists essentially of an up- 



Concrete Roads and Pavements. 147 

right cohimn j&tted with a large gear, by means of 
which the shafts bearing the testing apparatus are 
made to revolve about the column in a horizontal posi- 
tion, at a rate of speed governed by the rapidity with 
which the gasoline engine furnishing motive power 
is run. The engine is of 6 horsepower, and speeds 
varying at the wheels from 3 miles to 12 miles per 
hour are developed. 

The double wheels at the extreme ends of the hori- 
zontal shafts weigh 1,400 pounds each, and by means 
of a simple connection the exterior discs may be re- 
moved and similar discs of varying width, comparable 
to the widths of different tires, may be substituted. 

One of the most ingenious features of the appa- 
ratus is the fidelity with which the effect of horse- 
drawn vehicle traffic is simulated. Between the out- 
side disc, which represents the wheel of a wagon, and 
the inside ribbed disc, which encloses the mechanism, 
are placed five plungers, each bearing on its end a 
plate shaped like the bottom of a horse's hoof. These 
plates are furnished with four steel points similar in 
appearance to the calks worn by draft horses on their 
shoes in winter. As the wheel revolves the hoof -shaped 
plate strikes the pavement at a pressure of 150 pounds, 
produced by a cam geared to the horizontal shaft. As 
soon as the hoof-shaped plate has passed the point of 
contact it is released and a spring at the back repro- 
duces the ankle motion of a walking horse. 

In order to avoid making a single track for each 
wheel, which would result in all the wear coming on a 
definite circle drawn upon the pavements under test, 
Mr. McCabe has installed a worm gear, geared to a 
crank attached to the horizontal shaft. As the ap- 




(148) 



Concrete Roads and Pavements. 149 

paratus revolves one of the Avlieels is at the outside 
of the path to be tested and the other at the inside. 
As the wheels travel around the crank draws one in 
toward the center and pushes the other out from the 
center, with the result that at the end of a given num- 
ber of revolutions the wheels have changed places a« 
regards their distance from the center. 

The original test was made at 9 revolutions per 
minute about the circle, which gave a speed of 6.96 
miles per hour at the outside and a speed of 5.51 miles 
per hour at the inside of the track. 

Strangely enough, perhaps, the first section of 
pavement to give way was the granite block, which very 
soon loosened up in the grouting under the impact of 
the wheels. The failure of the granite was passed 
along to the next section, which was creosote block, 
and under this pavement the sand cushion caved con- 
siderably, causing the pavement to sink in the track 
which was covered by the wheels. The next brick section 
(Section 4), showed considerable wear and chipping. 
The cedar blocks were severely mashed and forced down 
into the sand. The brick section next in the path of the 
improvised traffic was completely destroyed, and part of 
this section had to be replaced before the test could 
be continued, because the destruction had gone so far 
as to interfere with the progress of the mechanism. 
The next section, also brick (Section Y), showed severe 
wear, and not all of this was due to the failure of the 
section before it, because where the worst break came 
did not follow the worst break in the preceding section. 
N'ext in line was the concrete section. The only bad 
break in the concrete was contiguous to a very severe 
break in the preceding brick section, where the impact 



150 Concrete Roads and Pavements. 

of the heavy wheel, coming from the broken brick pave- 
ment, could not help but do considerable damage. The 
abrasion of the concrete surface was regular and not 
more than % inch, while the granite was worn down 
more than 1 inch, and some of the brick fully 2 inches. 
The brick section, which had to be replaced while the 
test continued, was down more than 3 inches. 

This paving determinator was brought by the 
Universal Portland Cement Company to the Chicago 
Cement Show in January, 1913, and a number of sec- 
tions of pavement were tested at that time, the speci- 
mens later being shipped to Detroit and the tests con- 
tinued there. 

All concrete sections were of the same size, ap- 
proximately 3 feet 6 inches wide and 4 inches thick, 
reinforced at the center to prevent breaking in han- 
dling, with American Steel & Wire Company's triangle 
mesh, style No. 28. Ten sections with an 8-inch space 
between them formed a circular ring having an outside 
radius of 11 feet 3 inches. 

The concrete sections were all made in the week 
of Nov. 19 to 26, 1912, using Universal Portland ce- 
ment, clean, coarse sand and a coarse aggregate, either 
screened, washed gravel, crushed limestone or crushed 
granite. The concrete was well mixed by hand with 
sufficient water to produce a medium wet consistency, 
lightly tamped into the forms, the surface struck off 
with a straight-edge, finished with a steel trowel and 
then slightly roughened by brushing with an ordinary 
broom. The sections were cast indoors where the tem- 
perature varied during the time they were curing, 
from close to freezing, to about 70 degrees P. All 
sections were kept well sprinkled with water for three 



Concrete Roads and Pavements. 151 

days, and between Nov. 29 and Jan. 16 were sprinkled 
on two different occasions. The description of sections 
follows : 

Section No. 1. 1 part cement, I'Vz parts sand and 3 parts 
1/4 to 11^ inch screened, washed gravel; one edge of section 
protected with Baker metal plate. 

Section No. 2. 1 part cement, li/^ parts sand, and 3 parts 
of a mixture composed of 4 parts 1 to ll^ inch and 3 parts i/4 
to 1 inch crushed Wisconsin granite. 

No. 3. 1 part cement, 2i^ parts sand and 5 parts ^ to 
IMi inch screened washed gravel. 

No. 4. 1 part cement, l^/^ parts sand and 3 parts i^ to 
1 inch crushed limestone. 

No. 5. 1 part cemeni, 2 parts sand and 4 parts i/4 to 
11/^ inch screened washed gravel, one edge of section pro- 
tected with Baker metal plate. 

No. 6. 1 part cement, 2 parts sand and 3 parts % to 
lyz inch screened washed gravel. 

No. 7. Wearing surface 2 inches thick, 1 part cement, 2 
parts clean, coarse sand; base a 1:3:5 gravel concrete. 

No. 8. Wearing surface 2 inches thick, 1 part cement, 2 
parts of a mixture composed of 1 part i/4 inch granite screen- 
ings and 2 parts ^ to % inch crushed granite. 

No. 9. 1 part cement, 1% parts sand and 3 parts i/4 to 
1^/^ inch crushed limestone. 

No. 10. 1 part cement, 2 parts sand and 4 parts i/4 to 
11/^ inch crushed limestone. 

No. 11. 1 part cement, 2 parts sand and 4 parts crushed 
granite same as used in section No. 2. 

At the cement show the machine ran for a total 
of a little over 63 hours, each wheel in that time 
making 18,978 complete revolutions, the speed of the 
wheels varying from 3.06 miles per hour when travel- 
ing the inner circle of the path, up to a speed of 3.86 
miles per hour in traveling the outer circle. 

The work in Detroit in continuing the test was 
in charge of *a representative of the Inspection Bureau 
of the Universal Portland Cement Company. The 
original 8-inch concrete floor put down in the eastern 
yards of the Detroit Department of Public Works to 



152 Concrete Roads and Pavements. 

receive the determinator, was used for a foundation. 
On this was placed a 2%-inch bed of cement-sand mor- 
tar, in a mixture of 1 :!%, to bring the test sections up 
to the proper leveL Over this was run % inch of 
cement grout, in which the slabs to be tested were 
bedded. The concrete pavement sections put down in 
Detroit on this mortar and grout foundation were ar- 
ranged as shown in the accompanying diagram, the 
numbers corresponding to the numbers given to the 
test specimens above. 

Between sections there was a joint 8 inches wide 
made of 4-inch creosoted wood block put in with hot 




Location of Slabs Under Determinator. 

pitch and gravel. Soft steel plates were used at the 
edges of the concrete slabs. At the outset the deter- 
minator was run at 8% revolutions per minute, which 
gave a speed of 6.6 miles per hour at the outer edge of 
the track, with a speed of 5.2 miles per hour at the 
inner circumference, or an average speed of 5.9 miles 



Concrete Roads and Pavements. 153 

per hour. This speed was maintained for 5,700 revo- 
lutions of each of the wheels of the determinator, and 
the pounding was so great as not fairly to represent 
vehicle traffic on a pavement. 

Before proceeding with the test in Detroit, three 
of the five plungers on each wheel were removed, leav- 
ing two to a wheel, which seemed to he fairly compara- 
ble to ordinary vehicle traffic with two horses and eight 
hoofs to four wheels. 

After the 5,700 revolutions had been made, the 
speed was reduced to 6% revolutions per minute or 5 
miles per hour at the outer circumference, 4 miles 
per hour on the inside, or an average of 4.5 miles. 
This speed was maintained until a total of 20,400 revo- 
lutions had been made, so that those slabs which had 
been previously tested in Chicago underwent a total 
w^ear of nearly 40,000 revolutions. 

In this connection it may be remembered that in 
the first test with the paving determinator at Detroit, 
under the direction of the Department of Public Works, 
some of the brick pavement sections had practically 
gone to pieces when 6,000 revolutions had been 
made. 

Before the machine was started in Detroit, very 
careful level readings were taken on each one of the 
slabs in the track, using an architect's level reading to 
thousandths of a foot. Fifteen readings on each slab 
were taken within the wheel track, and one at each of 
the four corners of each slab outside the wheel track. 
There were other readings after 12,400 revolutions had 
been made, and final reading at the completion of the 
test, after 20,400 revolutions. Final readiu^s showed 
wear on the various slabs as follows : 



154 Concrete Roads and Pavements. 

Average wear after 
20,400 rev. 
Slab No. (given in inches) 

1 0.19 

2 0.11 

3 1.38 

5 1.77 

6 0.24 

7 0.26 

8 0.18 

9 0.13 

10 0.44 

11 0.16 

In a resume of the observations made after the 
test the Inspection Bureau outlines the following : 

Sections I^os. 3, 10 and 11 had had no wear pre- 
vious to the test in Detroit. Section l^o. 5 was some- 
what rough from previous wear when it was put down 
in Detroit. 

Sections Nos. 3 and 5 showed the concrete to be 
unsatisfactory for wearing surfaces. Section 'No. 3 was 
a mixture of 1 part cement, 2% parts sand, and 5 parts 
gravel, screened, washed and graded from % to 1% 
inches. Section No. 5 was a mixture of 1 part cement, 
2 parts sand, 4 parts Vk to 1% inches screened, washed 
gravel. Both of these sections were worn down to the 
reinforcing metal and Section No. 5 was worn so badly 
after 12,000 revolutions in Detroit, or a total of 31,000 
revolutions, that it was necessary to use gravel to help 
the wheels of the determinator over this slab. 

Section No. 2, which is one of those also used in 
Chicago, was still in perfect condition at the end of the 
test. This section is made of 1 part cement, 1% parts 
sand, and 3 parts of a mixture composed of 4 parts 
1-inch to 1%-inch and 3 parts %-inch to 1-inch crushed 
Wisconsin granite. This is the identical mixture, al- 
though not the samQ ^^gregate, used by the County 



Concrete Roads and Pavements. 155 

Koad Commissioners in the roads of Wayne County. 

Section ISTo. 8, a slab which was made in two 
courses having a wearing surface 2 inches thick, or 1 
part cement and 2 parts of a mixture composed of 1 
part %-inch granite screenings and 2 parts % to %- 
inch crushed granite, was not so satisfactory as section 
E'o. 2. The larger aggregate used in the one-course 
pavement therefore seemed to be better for heavy traffic. 

Section No. 9, made of a mixture of 1 part cement, 
1% parts sand and 3 parts 1%-inch crushed limestone, 
wore very smoothly, the wear of the stone being uni- 
form with that of the mortar which bound it. The 
next leaner mixture of the same materials, however, 
did not prove to be satisfactory. This is shown by 
section N'o. 10, made of a mixture of 1:2:4 cement, 
sand and crushed limestone, in which the stone wore 
roughly and unevenly and indicated that a continuation 
of the test would render it unsatisfactory. Section l^o. 
1 and section No. 6 wore uniformly, but with a slightly 
rough surface which, however, seems to be rather ad- 
vantageous than otherwise, because it gives a good 
foothold. 

Section No. 1 is practically identical with the 
mixture now used in Wayne county. It consists of 1 
part cement, 1% parts sand and 3 parts ^A to 1%-inch 
screened washed gravel. One edge of this section was 
protected with Baker metal plate. Section No. 6, sim- 
ilar to section No. 1, though rather more lean, .was 
made of 1 part cement, 2 parts sand and 3 parts 
screened washed gravel, of the same size as in section 
No. 1. Section No. 7, having a wearing surface 2 
inches thick of 1 :2 mortar in which clean, coarse sand 
is used, with a base consisting of a 1 ;3 ;5 mixture of 
gravel concrete, wore very uniformly. 



156 Concrete Roads and Pavements. 

Section ]^o. 11, consisting of a mixture of 1 part 
cement, 2 parts sand and 4 parts crushed granite, 
answering the same description as that used in No. 2, 
proved to be satisfactory by showing even wear, with a 
rough surface for good foothold. The objection to this 
mixture lies in the difficulty of obtaining a smooth 
surface without depressions, which is a most important 
requirement. The 1 :2 :4 mixture worked so badly, 
that although the slabs were made under laboratory 
conditions, it was impossible to finish section "No, 11 
smoothly and the hammering caused by unevenness 
resulted in a depression at one corner. 

The tests have demonstrated that a satisfactory 
wearing surface, under the most severe trafiic condi- 
tions, can be obtained with a 1 :1% :3 mixture, of ce- 
ment, clean, coarse sand and coarse aggregate consist- 
ing of well graded, screened, washed gravel, or graded, 
crushed limestone, ranging in size from i/4 to 1% inch. 

A 1 :2 :4 mixture with either of these materials, or 
mixtures containing less cement, will not withstand 
the impact and abrasion of trafiic in a degree at all 
comparable to the richer mixture. 

A 1 :2 mortar, made with clean, coarse, well graded 
sand, will withstand the effect of heavy traffic satis- 
factorily, although the wear is greater than on surfaces 
containing coarser material. 

Gravel containing a small percentage of soft stones 
is objectionable because the soft stones give points for 
the wear to start. For this reason crushed stone, con- 
taining material of uniform hardness, shows equal 
value to gravel, consisting of harder particles, but 
with a small proportion of soft pebbles. 



Concrete Roads and Pavements. 157 

Criisliecl Wisconsin granite, graded in sizes from 
V4, to 11/2 inches, was, nnqnestionably, the best ma- 
terial nsed for coarse aggregate in the slabs tested. 

Unevenness of surface finish, due to poor work- 
manship, causes pounding under heavy traffic and de- 
velops holes in the pavement which, if smooth, would 
withstand the same traffic perfectly for an indefinite 
period. 

Severe Test on Concrete Base. Because of com- 
plaints to the effect that the concrete base being laid 
on the new California state highways is not sufficiently 
thick to make it permanent, the highway commission de- 
cided to make a test, and this was done on January 22, 
1912, just north of Fresno. A report of the test was 
submitted by J. B. Woodson, sixth division engineer, t(« 
A. B. Fletcher, chief engineer of highway construction. 

According to the report of the Fresno office on the 
test made on January 22, the concrete at that point was 
laid on December 19, and was therefore 35 days old 
when tested. On examining a piece of fractured pave- 
ment it was still moist for the full thickness, as the 
weather at this time of the year is not conducive to 
rapid drying. The concrete would therefore probably 
have stood a greater strain if thoroughly dry. 

A trench 2 feet wide and 4 feet long was dug 
underneath the pavement, 12 inches from the edge, leav- 
ing the concrete over this trench without any support. 

The rear wheel of a 10-ton road roller was then rmi 
over this concrete slab in many positions. 

Wlien the wheel was run over the pavement 12 
inches from the edge there was no effect on the concrete. 
When it was run over the pavement 6 inches from the 
edge, there was still no effect. 



158 . Concrete Roads and Pavements, 

On the third test, the wheel was run over the con- 
crete 6 inches from the edge and stopped in the center 
of that portion of the concrete directly over the trench, 
also without any effect. When the edge of this wheel 
was run over the span, flush with the edge of the pave- 
ment, there was a slight spring. 

The fifth test consisted of running the wheel flush 
with the edge of the pavement, but also over a block of 
wood 2 inches thick, 4 inches wide and 8 inches long, 
placed 12 inches from the edge. There was a very 
noticeable spring as the wheel passed, but no fracture of 
the pavement. 

The test that finally fractured the concrete con- 
sisted of running the wheel over the span flush with the 
pavement and over the block that was placed on the 
span, 6 inches from the edge. The concrete failed to 
hold on this test. 

IsTotwithstanding the fact that the concrete was still 
moist, the local division office reported that the results 
seemed to be all that could be desired, as the concen- 
tration on the 4-inch block was almost 3% tons, or about 
1,666 or two-thirds of a ton to the square inch, on the 
unsupported base. 

The local division engineer made the following 
conclusions as to the durability of the road, in his re- 
port : 

^Tn view of the fact that the concrete did not frac- 
ture when tested 12 inches from the unsupported edge 
with the above concentrated load, and will never be 
called upon to bear such a load under actual trafiic con- 
ditions, I believe we are justified in stating that the 
4-inch concrete base properly constructed as the above, 
will stand any reasonable loads." 



CHAPTEK XII. 

Bridges and Culverts. 

This is a subject which is worthy of an entire sepa- 
rate treatise and which can necessarily be treated only 
in outline in a single chapter here. It is one which 
is so closely related to highway betterment, however, 
that this volume should at least call attention to the 
great advantages of concrete for this class of struc- 
tures. 

If a roadway is to be of a permanent material, one 
which largely eliminates the items of repairs and re- 
building, the bridges and culverts should also be of such 
a material, else much of the advantage will be lost. A 
smooth, durable roadway will be of little value in a 
spring freshet if the bridges crossing it have been car- 
ried away; nor will it be of much advantage to the 
farmer hauling a heavy load to market if some culvert 
of primitive type has collapsed. 

With the rapid increase in the amount and weight 
of traffic, an increasing amount of attention is being 
given to this subject. 

In repairs alone, entirely outside of new construc- 
tion, a great amount of money is spent wastefully. 
When it is considered that the major portion of the 
money might have been saved had a more enduring 
form of structure been adopted in the first instance, it 
becomes apparent that true economy lies in that class 
of construction which is permanent, and that the short- 
sighted policy which adopts a cheap form merely be- 
cause it is cheap results really in a waste of money. 

159 



160 Concrete Roads and Pavements. 

In view of the foregoing statement, it seems that it 
should be clear to every official who has anything to do 
with the construction of culverts or bridges, that he 
should bear constantly in mind the fact that permanent 
structures are the cheapest, and cause the culverts of his 
town to be built in a manner to forever eliminate the 
repair expense, which at the present time forms such 
a large item of cost. 

There are several kinds of material for the con- 
struction of such bridges, such as : 

1. The wooden bridge, with pile bents. 

2. Steel frame, or superstructure, on piling. 

3. Steel superstructure on masonry abutments, 
with wood floor. 

4. Steel superstructure on abutments, with a con- 
crete floor. 

5. Large sewer-pipe or tile. 

6. Culverts of smooth or corrugated steel pipe, 
galvanized or painted. 

Y. Bridges and culverts of reinforced concrete, of 
any span or shape."^ 

A bridge or culvert on any highway must necessar- 
ily be such as to require little attention or care. It is 
safe to say that we hardly have a bridge on any of our 
highways that is regularly inspected from time to time. 
N^ot until a plank in the floor is broken, or a washout 
carries away the filling from the approaches of the 
bridge, or by some condition it is made a dangerous 
crossing, is it inspected or looked after. In other words, 
it is necessary to build bridges or culverts that require 
little care and maintenance. 



*This classification, and the discussion of some of the types, 
foHows very largely a paper given by Mr. James A. Mortland 
before the Nebraska Cement Users' Association. 



Conercfc Bonds and Pavements. 161 

Wooden bridges surely do not meet this require- 
ment. They require constant attention, and even then 
are often a menace to safety. In many places, too, they 
are carried to a much greater span than would otherwise 
he necessary, owing to the fact that it is impracticable 
to fill in the approaches. One case is cited where a 
concrete arch of 35-foot span replaced an 80-foot 
wooden bridge, and another where a 40-foot concrete 
structure replaced one of wood of 66-foot span. 

To make culverts of wood, where any amount of 
earth is to be placed on top, is temporizing and in the 
end will cost more to replace. 

Bridges with a steel superstructure on piling, with 
wooden floors, are not much better than the wooden 
bridges and are of no more use in making our highways 
permanent than an all-wooden structure. Steel bridges 
with concrete or masonry abutments and wood floors 
are not at all so desirable, as the floors rapidly wear 
out, the life of a plank floor on a bridge with ordinary 
travel is not more than five j'^ears, with many new planks 
needed from time to time in that interval. Steel bridges 
on concrete abutments, with concrete floors, are quite 
satisfactory, but are likewise expensive ; in fact, it is 
possible to construct a concrete bridge as cheaply in 
ninety-nine cases in a hundred, and the concrete bridge 
has the advantage of not requiring painting, and suf- 
fers no de2:)reciation from the elements. 

So far we have considered bridge's for living 
streams or for locations where it would not be policy to 
narrow the waterway to any great extent. But in many 
localities one bridge in five spans a living stream, the 
other four spanning gullies and dugouts that are 
dry for a greater part of the year. Thus we have a 




(162) 



Concrete Roads and Pavements. 163 

condition presenting itself to the highways as it has to 
the railroads ; and we find the railroads have almost in- 
variahlv constrncted such a waterway by means of cul- 
verts nnder their tracks, so as to carry a normal rain- 
fall, and filling on top, giving them a continuous road- 
bed ; with a flood, the water may be held back for a 
time, but soon can get away without any great damage 
from backing up. It is possible to adopt this method of 
placing culverts in such places on the highways, and by 
filling on top a roadway is obtained that is permanent 
and with no danger of ever giving out. By reducing 
the length of the bridge and placing a culvert the result- 
ant cost of a permanent culvert is oftentimes less than 
the amount it would take to build a wooden bridge 
necessary to span the ditch. 

Here are two instances of reducing the waterways, 
or rather of filling up an open ditch : First, where three 
wooden bridges had been built in thirty-five years, the 
last one was 44 feet long, and it had served its time, so 
it was removed and a concrete culvert was built with 
inside dimensions of 4x5 feet ; and this culvert has 
proved ample for all the water that can flow in the ditch. 
Another bridge 56 feet long which has grown from a 
span of 16 feet in ten years, was rendered unsafe by the 
bank slipping in, breaking ofl the piling. This was re- 
placed with a concrete culvert five feet square and thir- 
teen feet of dirt placed on top, making a permanent 
roadway instead of having a plank floor over a deep 
gulley. These two cases show that often there is a plank 
roadway where it would be possible to have a dirt road. 
Then such gullies or washouts are usually at the foot of 
a hill or between hills, and the cutting down of the hills 



164 Concrete Roads and Pavements. 

and filling in of the culvert improves the whole road 
and makes a permanent improvement. 

Having these conditions, it is well to consider the 
various materials available for constructing such cul- 
verts as needed. 

Large sewer-pipe has been used with varying de- 
grees of success. Much depends on the placing of the 
pipe and the character of foundation on which they rest,. 
and in the cementing of the joints. The disadvantage 
is in the frequent unequal settling of the pipe when the 
earth is filled in, and this causes a break in the flow of 
the water and it will tend to fill up the pipe, likewise 
increasing the chances of undermining the pipe. To 
make a concrete footing for the pipe and to carry this 
up the sides to the horizontal diameter adds greatly to 
the cost, while it improves the value of the pipe as a 
culvert. 

End walls over the top of the pipe are needed to 
prevent the fill from washing down into the opening; 
also wing walls are necessary to hold the dirt on the 
sides. The attaching of these walls to the pipe is a dif- 
ficult matter and is usually very unsatisfactory, owing 
to the fact of not being able to get a good bond between 
the pipe and the concrete or mortar of the walls. 

There have been many types of circular steel cul- 
verts brought into the market in the past few years hav- 
ing some merit, but the fault is rusting. The same ob- 
jection of attaching wing and end walls to this type of 
culvert as with sewer pipe is true. For any given area 
of carrying capacity it is possible to construct concrete 
culverts as cheaply as tlie stool i)ipe, and provide the 
concrete culvert with wing and end walls. 

Concrete Slabs, T-Bcanis, and Fein forced Con 



Concrete Roads and Pavements. 165 

Crete. The simplest form of concrete construction for 
bridees or culverts is the concrete floor or slab, corre- 
sponding to the wooden plank Hoor. The concrete slab 
may be used for greater spans than the plank floor, and 
it may also be strengthened for greater spans by con- 
structing concrete beams beneath the floor to support 
it. This is then known as the ^'T-beani" type of con- 
struction, from its resemblance in form to the capital 
letter T." 

These types of concrete construction may be 
strengthened further by placing steel rods, expanded 
metal, or woven-Avire cloth near the bottom of the slab, 
and steel rods near the bottoms of the beams. The ad- 
vantages of using the steel reinforcement are that it has 
a greater tensile strength than concrete and that its lo- 
cation in the lower part of the concrete slab or beam 
brings it into tension when the beam is loaded. More- 
over, the compressive strength of concrete is greater 
than its tensile strength, and therefore the steel strength- 
ens that part of the concrete structure which is subject 
to tensile stresses and is most liable to fail first. 

This method is therefore more economical and 
makes it possible to bridge greater spans, within prac- 
tical limits of cost, than can be done with plain con- 
crete alone. 

Box Culverts. The application of the concrete 
slab is to be found first in the construction of box cul- 
verts. Public highways in this countrj^ are crossed by 
many small open ditches. Many of these ditches are 
provided with wooden stringers and plank floors, which, 
however, are so nearly worn out and are in such poor 



*In the description of these types the author foUows Bulletin 
No. 43 of the Office of Public Roads. 



166 



Concrete Roads and Pavements. 




Concrete Boads and Pavements. 167 

condition that thcv do little more than invite accident. 
There is continual annoyance and expense in keeping 
these in repair, and this may all be avoided by build- 
ing small concrete box culverts at these places. 

The box culvert gets its name from its similarity 
to a box with open ends. It has a floor, which may be 
of plain concrete or may be paved with stone. The two 
sides and wing walls at the two ends may be of plain 
concrete or reinforced with steel, but the cover and par- 
apets should always be of reinforced concrete. 

The sketch shown on page 166 is made from a 
working plan j)repared in the Office of Public Roads for 
a concrete box culvert, which has an opening 2 feet wide 
by 2 feet high. 

This type of construction is practical under the 
majority of conditions for spans up to about 8 feet, 
which, as a matter of fact, forms a large percentage of 
all the culverts needed. Conditions may occur where 
it will be practicable to apj^ly the box type, with some 
modifications, to greater spans than those mentioned, 
such as where the foimdation is soft or liable to much 
erosion from swift currents. The floor may then be 
reinforced with steel, so that it will have greater 
strength to act as a beam to distribute the load over a 
greater area. It may also be extended back of the side 
walls to act as a footing. With suitable '^cut-ofl" walls 
to prevent current of water from running beneath this 
floor, the foundation will be well protected from erosion. 
Under such conditions this modified type, with further 
modifications in the cover, may be practical for spans 
up to 20 or 30 feet. 

Beinforced Concrete Slab Culverts. The length of 
the spans over which reinforced concrete slabs mav be 



168 Concrete Boads and Pavements. 

built within the limits of practicability and safety de- 
pends mnch npon the loads to be carried. The depth 
and amonnt of fill over the culvert, which may dis- 
tribute the effect of the concentrated load, is also an im- 
portant factor. 

On main roads, where concentrated loads, such as 
road rollers or traction engines, are to be provided for 
and the depth of fill over the culvert is sufficient only to 
provide a cushion of earth from 1 to 2 feet in depth, 
the concrete slab is practical for spans up to about 10 
or 12 feet, whil'e for greater spans than this, under 
these conditions, other types better adapted to the longer 
spans should be used. 

Under conditions of less severe loading the spans 
for the slab may be increased up to 16 or possibly 20 
feet, but it does not seem advisable to use them for 
these greater spans in view of the possibilities of a nom- 
inal future grow^th of traffic requirements. 

Beinforced Concrete T-Beam Culverts. The rein- 
forced concrete T-beam type of construction supple- 
ments the slab type and begins to be practical in point 
of economy at the point where the slab ceases to be eco- 
nomical — that is, for spans from about 10 to 12 feet 
and more — under the conditions of concentrated loads, 
such as road rollers or traction engines. This type of 
construction has been designed for spans up to 50 feet 
long, but whether or not it is practical for spans as 
great as that may depend upon several conditions, which 
must be carefully determined in each individual case. 

Concrete-Steel I-Beam Culverts. One of the best 
types of culverts for spans from 10 to 30 feet long is 
the steel I-beam incased in concrete, upon Avhich rests a 
relativelv thin concrete slab which forms the cover for 



Concrete Roads and Pavements. 169 

the cnlvert. The slab is designed to carry the load for 
a span eqnal to the distance from center to center of the 
steel I-beanis, while the beams are designed to carry the 
load over the clear span from one side wall or abutment 
to the other. 

Among the best features of this ty})e of construc- 
tion are its safety and ability to withstand severe and 
unfavorable conditions, such as the unequal settlement 
of abutments, which may cause cracks in the concrete 
that Avould cause other types to fail. In this type, how- 
ever, the load is carried principally by the steel I-beams, 
whose strength is not destroyed by the settlement of the 
abutments. 

Many structures of this type have been built with- 
out incasing the I-beams in concrete, but by merely 
painting the beams instead, to protect them from rust. 
The painting, hoAvever, must be repeated every few 
years, at some considerable expense. There is, of 
course, a great possibility that this painting may never 
be done, and the better way is decidedly to incase the 
beams in concrete during- the construction, and thus 
protect them j^ermanently. 

This type also admits of arch construction between 
the beams for the floor system. By this means space 
may be saved in the depth of the floor system that may 
be of value in locations where the area of the waterway 
or the "head room" is a controlling factor. 

Reinforced Concrete Arches. The reinforced con- 
crete arch has an advantage over the plain concrete arch 
in the fact that the curve of the reinforced structure 
may be made more nearly flat than the plain concrete 
arch, and thereby save in the total height of the struc- 
ture. This permits it to be used where it otherwise 



lYO 



Concrete Roads and Pavements. 



could not be. Under favorable conditions there may be 
an additional advantage in point of economy, althougb 
this can not be stated generally as true in all cases. 

The steel reinforcement in the arch serves the same 
jDurpose as in the concrete slab — that is, to increase the 
strength of the arch rib where the concrete has excessive 
tensile stresses. In some cases, however, the concrete is 
also reinforced against compression. It is also possible, 
when steel reinforcement is used, to reduce the quantity 
of concrete in the arch rib from the amount that would 
be required for a plain concrete arch. The reinforced- 
arch type of construction may be used for practically 
the same spans as stated for the plain concrete arches. 

Cost of Box Culvert. The cost data below is for a 
small 4x5 box culvert, 26 feet long, built according to 
the designs here shown, which are taken from a bulletin 
issued by the !North Carolina Geological and Economic 
Survey. 

The w^ork was done by a regular county concrete 
gang, composed of a foreman, seven men and two teams 
with drivers, and was completed in four days of 10 
hours each. The excavation was light, but the soil was 



Use 2'4' for spang 3ff and under 
4'>6* for spans from 3ft' "" 

Uac 2''4' for heights 3ffand undo 
4'«4' for heiqhfs fronn 3f> 




INLtT END rOBM 



Use oufside forms where 
earfh cannot- bftctrt- smooVh. 

Use 2'plank(no+ nailecj)for flooring. 

Use I'or li" lurnbsr for wings and inside forms. 

PLAM OF F-OF2MS o"^ 
YPICAL. BOX CUL-VEIISTS 

SBA,NS fc. hElOMTS "' 



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(171) 



172 Concrete Boads and Pavements. 



of a hard, black nature that was hard trimming. Water 
for mixing had to be hauled two miles. 

Sand gravel was used for aggregate in the concrete. 
The gravel contained a slight excess of sand and worked 
up in the proportions given. Mixing was done by hand 
with negro labor. Twisted square steel bars were used 

for reinforcing. 

Labor. 

Foreman, 40 hours @ 25c $10.00 

Culvert excavation, 9 cubic yards @ 80c 7.20 

Labor on forms 14.00 

Mixing and placing, 120 hours @ 15c 18.00 

Hauling water, 20 hours @ 30c 6.00 

Cutting and placing steel, 10 hours @ 15c 1.50 

Cleaning up and removing forms, 10 hours @ 15c. 1.50 

$58.20 
50% salvage on forms 7.00 

$51.20 
Moving on and off job 10.00 

Total labor at culvert $61.20 

Material (Laid Down at Culvert). 

Cement, 26 barrels @ $1.80 $46.80 

Hauling cement, 12 1/^ hours @ 30c 3.75 

Gravel, 18i/^ cubic yards @ $1.10 f. o. b. cars 

Ennis, Texas 20.35 

Hauling, l^Vz cubic yards, 46 hours @ 30c (75c 

per cubic yard) 13.80 

Steel, 1,072 pounds @ 2i^c 26.80 

Hauling steel, 2 hours @ 30c 60 

Lumber, 1,000 feet B. M. @ $25.00 25.00 

Hauling lumber, 3 hours @ 30c 90 

$138.00 
75% salvage on form lumber 18.75 

Total cost of material at job 119.25 

Total cost of job $180.45 

Cost per cubic yard of concrete in place, exclusive of 

culvert excavation 9.37 

Cost per cubic yard of concrete in place, exclusive 

of excavation and steel 7.85 



Concrete Roads and Pavements. 173 

The quantities were as follows : 14^2 cubic yards 
of 1:3:5 concrete; 4 cubic yards of 1:2% :4 concrete; 
432 pounds of %-incli steel; 640 pounds of V2-incli steel, 
and 1,000 feet B. M. of lumber. 

Luten Truss. On page 174. is sllo^^^^l a design for 
small bridges and culverts using a built-up reinforce- 
ment known as the Luten truss. It is intended for slab 
bridges of spans up to 20 feet and for girder bridges of 
greater length. The steel is in the form of a rigidly 
constructed unit clamped together with locked wedges. 
It is set directly on the forms and the concrete poured 
around it. 

Size of Culverts. A number of formulas, designed 
to aid in estimating the size of culverts, and based on 
the considerations stated, have been proposed. The most 
common of these is Myer's formula, which states the re- 
lation between the drainage area as follows : 

The required area of waterway in square feet is 
equal to the square root of the drainage area in acres, 
multiplied by a number varying from 1 to 4, depending 
on the character of the watershed. For slightly rolling- 
ground, this number is taken as 1 ; for moderately hilly 
ground, at 1^2 or 2 ; and for steep, rocky ground, at 4. 

For a drainage area of 40 acres, this would mean 
that level or slightly rolling ground would require about 
6 square feet, which is a 2x3-foot box, or a 36-inch 
pipe ; if moderately hilly, it would require about 12 
square feet of opening, which is a 3x4-foot box or a 48- 
inch pipe ; or, if the ground is very steep and rocky, 
from 25 to 30 square feet, meaning that a 5x6-foot cul- 
vert or a 6-foot pipe will be required. 

There are other similar formulas, but all are valu- 
able simply as guides to the judgment in forming an 
opinion as to the reliability of any information gathered 




(174) 



Concrete Eoads and Pavements. 175 

from local sources. It can readily be seen that the selec- 
tion of the constant multiplier is left entirely to one's 
judgment, and this makes the result obtained by the 
use of the formula almost wholly a matter of opinion. 

A very important thing to be taken into account is 
the height of the fill over a culvert. If a culvert dis- 
charges under a head, the discliarge is increased very 
rapidly as the head increases ; so that if the fill is deep, 
and the water can be dammed to some extent, it is safe 
to use a smaller culvert than Avould be safe Avith a shal- 
low fill. 

The shape of the opening in a culvert is of little 
significance, provided that the area of the opening is 
sufiicient. For the larger sizes, it certainly is easier to 
build the culvert rectangular in form, Avith a fiat top, 
principally because of the fact that the forms can be 
built more easily, and Avith less cutting of lumber. 
There is added advantage in that for any giA^en span a 
rectangular opening Avill give more AvaterAvay than an 
arched opening. Also the Avidth of the opening re- 
mains constant, regardless of the height to AAdiich the 
Avater may rise. 

It is usually an advantage in the larger culverts to 
liaA^e a separate foundation for each side Avail, but in the 
smaller culverts the Avhole bottom should be paA^ed, as 
in this Avay the foundation is protected from scouring. 
Especial care should be taken to have the cuh^ert dis- 
charge in such a Avay that the loAver end Avill not be 
undermined. 

The forming of small culverts is a matter of some 
difficulty : though not so much the forming itself as the 
removal of the form after the culvert is set. Mr. M. W. 
Torkelson, bridge engineer for the Wisconsin HigliAvay 
Commission, states that he has seen numerous small 



17^ Concrete Roads and Pavements. 

culverts with a portion of the form lumber remaining 
fast in the culvert. This is a serious condition, because 
it is apt to cause the culvert to become filled with trash, 
effectually stopping the flow of water through the cul- 
vert and rendering it liable to a washout. He believes 
that much of this trouble could be obviated by building 
the forms less tight, and covering open spaces in the 
forms with building paper fastened to the forms with 
small tacks. It is also thought that the boards compos- 
ing the forms could be leveled in such a way as to make 
their removal easier. Also, no culvert should ever be 
less than 18 inches square if there is room to permit. 

In the building of these smaller culverts, the cost 
of forming is one of the most important items. The 
amount of concrete required is very small. The labor 
of excavation, etc., is also usually slight, but the trouble 
of forming and of removing forms is considerable. The 
Avriter believes that these small culverts can best be 
built with some permanent forms which can be easily 
set up and conveniently removed as soon as the concrete 
has set reasonably well, and then used at another point. 
It seems certain that such a form can best be built of 
metal, especially for a culvert with a circular opening. 
There are several such forms on the market. 

Mr. Torkelson, quoted above, says that it is the 
practice of the Wisconsin Highway Commission to use 
concrete wherever possible. It believes that where ma- 
terials are reasonable in price, and the cost of founda- 
tion work not too great, that concrete is the most eco- 
nomical material. It recommends the following general 
rule for design : For the shorter spans up to about 25 
feet, flat slab construction is recommended ; for spans 
from 25 to 40 feet, the through girder or arch type; 
and for greater spans, arches. 



CHAPTER XIII. 

Sidewalks, Cuebs and Gutters. 



This is a subject closely allied to the general topic 
treated in this volnnie, and yet one on which we need 
say little more than to call attention to the standard 
specifications of the Xational Association of Cement 
Users, printed in Appendix K and Appendix L. 

Concrete has come to be the standard material for 
these purposes, and its utility is never questioned. In 
very few cities indee-d is anything else now used for 
the construction of sidewalks, curbs and gutters. In a 
few smaller places the plank sidewalk is still allowed, 
but even in these towns most of the residents build with 
concrete of their own accord, and the city councils are 
rapidly seeing the wisdom of this course and are one 
by one making the concrete sidewalk mandatory. 

In isolated cases, too, stone curbing is used; but 
they are so infrequent as merely to emphasize the gen- 
eral use of concrete for this purpose. 

Concrete for these purposes has everything in. its 
favor. It is long lived, pleasant to the tread, sightly; 
and what is perhaps more important from the stand- 
point of city economy, it does not become dilapidated, 
causing accidents and involving the city in countless 
damage suits, as is the history of the plank walk. Tak- 
ing all these things into consideration, concrete is by 
far the cheaper material in the end. 

A number of years ago many people hesitated to 
put down concrete walks because of the fear that they 

(177) 



178 Concrete Bonds and Pavements. 



would not get good workmanship. This is no longer 
true. The method for the laying of such walks has 
become standardized, as embodied in the specifications 
given in the Appendix, or in the specifications of pro- 
gressive cities;- and knowledge in regard to .concrete 
has become more widely disseminated, so that almost 
any reputable contractor can ])e relied upon to do in- 
telligent and satisfactory work. 

It is also true that improvements in methods, the 
gradual reduction in the price of cement, and the in- 
crease in competition in this line of work, have brought 
the price down considerably ; and with lumber con- 
stantly rising in price, a concrete walk no longer looks 
like an extravagance to the ordinary property holder 
as compared with plank. 

The perfection of metal forms for sidewalk, curb 
and gutter work is perhaps one of the most important 
developments in this branch of the industry within 
recent years, and is calculated to add still further to 
standardization and economy. 

Sidewalks, like jDavements, may be built in either 
one or two courses, the latter method being the one in 
most general use. It is probable, however, that the one- 
course walk is destined to grow in favor. 



APPEXDTX A. 

SPECIFICATIONS OF NATIONAL ASSOCIATION CEMENT 

USERS- 

ROADS AND PAVEMENTS. 

Materials. 

1. Cement. — The cement shall meet the requirements of 
the Standard Specifications for Testing Materials, and adopted 
by this Association (Standard No. 1). 

2. Fine Aggregate for Concrete. — Fine aggregate 'shall 
consist of sand, crushed stone or gravel screenings graded 
from fine to coarse and passing, when dry, a screen having 
1/4 -inch diameter holes; shall be preferably of silicious ma- 
terial, clean, coarse, free from dust, soft particles, loam, 
vegetable or other deleterious matter, and not more than 3 
per cent shall pass a sieve having 100 meshes per linear inch. 
Fine aggregate shall be of such quality that mortar com- 
posed of 1 part Portland cement and 3 parts fine aggregate, 
by weight, when made into briquettes, will show a tensile 
strength at least equal to the strength of 1:3 mortar of the 
same consistency made with the same cement and Standard 
Ottawa sand. In no case shall fine aggregate containing 
frost or lumps of frozen material be used. 

3. Aggregate for Wearing Course. — The aggregate shall 
consist of screened gravel or stone screenings from granite 
or other close-grained, durable rock, sufficiently hard to 
scratch glass, free from loam or other deleterious matter, 
mixed in the proportion of 3 parts passing a i/^-inch ring and 
retained on a screen having l^-inch diameter holes, and 2 
parts passing a screen having i/4-inch diameter holes, and 
retained on a screen having 50 meshes per linear inch. In no 
case shall aggregate for wearing course containing frost or 
lumps of frozen material be used. 

4. Coarse Aggregate for Concrete. — Coarse aggregate 
shall consist of inert materials, such as stone or gravel, 
graded in size, retained on a screen having i^-inch diameter 
holes; shall be clean, hard and durable, free from dust, 
vegetable or other deleterious matter, and shall contain no 
soft, fiat or elongated particles. In no case shall coarse 
aggregate containing frost or lumps of frozen material be 
used. The maximum size of the coarse aggregate shall be 
such as to pass a li/^-inch ring. 

5- Natural Mixed Aggregates. — Natural mixed aggregates 
shall not be used as they come from deposits, but shall be 

(179) 



180 Concrete Roads and Pavements. 

screened and remixed to agree with the proportions specified. 

6- Sub-base. — Only clean, hard, suitable material, not 

exceeding 4 inches in the largest dimensions, shall be used. 

7. Water. — Water shall be clean, free from oil, acid, 
alkali or vegetable matter. 

8. Coloring. — If artificial coloring matter is required, 
only mineral colors shall be used. 

9. Reinforcing Metal. — The reinforcing metal shall meet 
the requirements of the Standard Specifications for Steel 
Reinforcement adopted March 16, 1910, by the American Rail- 
way Engineering Association. 

Sub-Grade. 

10. Section.- — The sub-grade shall have a rise at the cen- 
ter of not more than 1-lOOth the width of the pavement. 

11. Depth. — (a) The sub-grade shall not be less than 12 
inches below the finished surface of the pavement. 

(b) The sub-grade shall not be less than 6 inches below 
the finished surface of the pavement. 

12- Preparation. — All soft and spongy places shall be re- 
moved and all depressions filled with suitable material which 
shall be thoroughly compacted in layers not exceeding 6 
inches in thickness. 

13. Deep Fills. — When a fill exceeding 1 foot in thick- 
ness is required to bring the pavement to grade, it shall be 
made in a manner satisfactory to the engineer. 

14." Drainage. — When required, a suitable drainage sys- 
tem shall be installed and connected with sewers or other 
drains indicated by the engineer. 

(Note. — When a sub-base is required, eliminate Paragraph 
11-b. When sub-base is not required, eliminate Paragraphs 6, 
11-a, 15 and 16. Unless 11-a is eliminated, 11-b is void.) 

15. Thickness. — On the sub-grade shall be spread a ma- 
terial as hereinbefore specified, which shall be thoroughly 
rolled and tamped to a surface at least 6 inches below the 
finished grade of the pavement. 

16. Wetting. — While compacting the sub-base, the ma- 
terial shall be kept thoroughly wet and shall be in that con- 
dition when the concrete is deposited. 

Forms. 

17. Materials. — Forms shall be free from warp, and of 
sufficient strength to resist springing out of shape- 

18. Setting. — The forms shall be well staked or other- 
wise held to the established lines and grades and their upper 
edges shall conform to the established grade of the pavement. 

19. Treatment. — All wood forms shall be thoroughly 
wetted and metal forms oiled before depositing any material 
against them. All mortar and dirt shall be removed from 
forms that have been previously used. 



Concrete Roads and Pavements. 181 

Expansion Joints. 

20. Width and Location. — Expansion joints not less than 
1/4 inch nor more than y^ inch in width shall be placed across 
the street or road, not more than 25 feet apart. When a curb 
or combination curb and gutter is used a i/^-inch joint shall 
be placed between it and the pavement. All expansion joints 
shall extend through the entire thickness of the pavement. 

21. Joint Filler. — The expansion joint filler for open 
joints shall be a suitable bitumen that will not become soft 
in hot weather nor hard and brittle in cold weather. Expan- 
sion joints may also be formed by inserting during construc- 
tion and leaving in place a total thickness of i/4 inch of tarred 
paper or tarred felt. 

22. Protection of Edges. — When required by the engineer 
in charge, the concrete at the expansion joints shall be pro- 
tected with metal. Unless protected by metal or filled wifh 
tarred paper or felt, the upper edges of the concrete shall be 
rounded to a radius of % inch- 
Measuring and IVIixing. 

23. Measuring.— The method of measuring the materials 
for the concrete, including water, shall be one which will 
insure separate uniform proportions at all times. A sack 
of Portland cement (94 pounds net) shall be considered 1 
cubic foot. 

24. Machine Mixing. — When the conditions will permit, 
a machine mixer of a type which insures the uniform pro- 
portion of the materials throughout the mass, shall be used. 
The ingredients of the concrete or mortar shall be mixed to 
the desired consistency and the mixing shall continue until 
the cement is uniformly distributed and the mass is uniform 
in color and homogeneous. 

25. Hand Mixing. — When it is necessary to mix by hand 
the materials shall be mixed dry on a water-tight platform 
until the mixture is of uniform color, the required amount of 
water added, and the mixing continued until the mass is of 
uniform color and homogeneous. 

26. Retempering. — Retempering, that is remixing the 
mortar or concrete that has partially hardened, with ad- 
ditional water, will not be permitted. 

TWO-COURSE PAVEMENT. 
Base. 

27. Proportions. — The concrete shall be mixed in the 
proportion of 1 sack Portland cement, 2^^ cubic feet fine ag- 
gregate, and 5 cubic feet coarse aggregate. 

28- Consistency. — The materials shall be mixed with 
sufficient water to produce a concrete of a consistency such 
that mortar will flush to the surface under light tamping, but 



182 Concrete Roads and Pavements. 



which can be handled without causing a separation of the 
coarse aggregate from the mortar. 

29. Placing. — After mixing, the concrete shall be handled 
rapidly into place and successive batches deposited in a con- 
tinuous operation, completing sections between expansion 
joints without the use of intermediate cross forms or bulk 
heads. Concrete shall not be used that has partially hardened. 
The concrete shall be well tamped to a surface the thick- 
ness of the wearing surface below the established grade of 
the pavement. Workmen shall not walk on freshly laid con- 
crete, and if sand or dust collects on the base, it shall be re- 
moved before the wearing course is applied. 

30. Reinforcing. — On streets more than 20 feet wide not 
having car tracks, the pavement shall be reinforced with 
wire fabric or with plain or deformed bars. The cross sec- 
tional area of metal shall amount to at least 0.041 square 
inches per foot measured parallel to the axis of the street, 
and at least 0.025 square inches per foot measured perpen- 
dicular to the axis of the street. The reinforcing metal shall 
be placed upon and slightly pressed into the concrete base 
immediately after the base is placed. Reinforcing metal 
shall not cross expansion joints and shall be lapped sufficiently 
to develop the strength of the metal. 

Wearing Course. 

31. Proportions. — The mortar shall be mixed in the man- 
ner hereinbefore specified in the proportion of 1 sack Port- 
land cement and not more than 2 cubic feet of aggregate for 
wearing course. 

32. Consistency- — The mortar shall be of a consistency 
that will not require tamping, but which can be easily spread 
into position with a template or straight edge. 

33. Thickness. — The wearing course of the pavement in 
residence districts shall have a minimum thickness of lYz 
inches, and in business districts a minimum of 2 inches in 
thickness. 

34. Placing. — The wearing course shall be placed im- 
mediately after mixing, and in no case shall more than 50 
minutes elapse between the time the concrete for the base 
is mixed and the time the wearing course is placed. 

35. Finishing.— After the wearing course has been 
brought to the established grade with a template or straight 
edge, it shall be worked with a wood float in a manner to 
thoroughly compact it and produce a comparatively smooth 
surface, free from depressions or inequalities of any kind. 
The finished surface of the concrete shall not vary more 
than % inch from a 2-foot straight edge placed upon the con- 
crete in any position. 

36. Coloring. — If artificial coloring is used, it must be 
incorporated with the entire wearing course and shall be 



Concrete Roads and Parenicnts. ISo 

mixed dry with the cement and aggregate until the mixture 
is of uniform color. In no case shall the amount of coloring 
used exceed 5 per cent of the weight of the cement. 

ONE-COURSE PAVEMENT. 

The general requirements of the specifications covering 
two-course work will apply to one-course work with the fol- 
lowing exceptions: 

37. Proportions. — The concrete shall be mixed in the pro- 
portion of 1 sack Portland cement to not more than 2 cubic 
feet of fine aggregate (paragraph 2) or aggregate for wear- 
ing course (paragi-aph 3) and 3 cubic feet of coarse aggre- 
gate passing a 1-inch ring. 

38- Placing and Finishing. — The concrete shall be placed 
and finished as provided for under "Two-Course Pavement," 
"Base" and "Wearing Course" respectively. 

39. Reinforcing. — When a one-course pavement is rein- 
forced the metal shall be placed at the middle of the section. 
The minimum amount of metal shall be as specified under 
"Two-Course Pavement." 

Crown. 

40. Amount. — All types of concrete pavement shall be 
given a rise or crown at the center of at least 1-lOOth but 
not more than 1-75 of the width of the pavement. A portion 
of this crown may be obtained by increasing the thickness 
of the pavement at the center rather than by laying a pave- 
ment of uniform thickness on a crowned sub-grade or sub- 
base. 

Protection. 

41. Treatment. — As soon as the concrete has hardened 
sufficiently to prevent being pitted, the surface of the pave- 
ment shall be sprinkled with clean water and shall be kept 
wet for at least four days. Concrete pavements on roads 
shall be covered as soon after finishing as it is possible to 
do so without damaging the surface, with at least 2 inches 
of dirt, which shall be kept wet for at least four days. Before 
covering with dirt, the pavement shall be sprinkled with 
water as above specified. The pavement shall not be open to 
traffic until the engineer so directs. 

42. Temperature Below 35° Fahr. — If at any time during 
the progress of the work the temperature is, or in the opinion 
of the engineer, will, within 24 hours drop to 35 degrees 
Fahrenheit, the water and aggregates shall be heated and 
precautions taken to protect the work from freezing for at 
least 5 days. In no case shall concrete be deposited upon 
a frozen sub-grade or sub-base. 

Shoulders. 

43. Construction. — On streets where the pavement does 
not occupy the full width of the street, and on roads, a gravel 



IS-i Concrete Roads and Pavements, 

or crushed stone shoulder at least 2 feet wide shall be con- 
structed on each side of the pavement. The surface of the 
shoulders shall have a slope away from the pavement of IV2 
inches per foot, and a thickness of 2-foot width adjoining the 
concrete, at least equal to the minimum thickness of the 
concrete. 

Wearing Surface of Bitumen and Fine Aggregate. 

44. Construction. — Where a wearing surface of bitumen 
and fine aggregate is used, it shall preferably be placed upon 
a one-course pavement, constructed as hereinbefore specified, 
but may be used also on two-course work. 

45. Expansion Joints. — Before applying the bitumen to 
the concrete, all open expansion joints shall be filled as here- 
inbefore specified. Where required by the engineer in charge, 
concrete at the expansion joints shall be protected with metal. 

46. Bitumen. — The bitumen shall be of a quality speci- 
fied by the engineer. 

47. Placing Wearing Surface. — After the concrete has 
hardened for at least 7 days the thoroughly cleaned dry sur- 
face of the pavement shall be covered with hot bitumen 
applied with a sprinkling wagon designed for the purpose, or 
with suitable hand sprinkling cans. The hot bitumen shall 
immediately be evenly distributed over the concrete by brush- 
ing with suitable brooms, and then covered with the required 
amount of fine aggregate (paragraph 3). 

48. Amount of Bitumen and Fine Aggregate. — Approxi- 
mately 'V2 gallon of bitumen shall be applied per square yard 
of pavement and approximately 1 cubic yard of fine aggregate 
shall be applied per 150 square yards of pavement. 

Protection. 

49. Open to Traffic. — The pavement shall not be open 
to traffic until the engineer so directs. 



APPEXDIX B. 

WAYNE COUNTY SPECIFICATIONS. 
Parties. 

For the sake of brevity, the Board of County Road Com- 
missioners for the County of Wayne will be referred to in 
these specifications as the Board; the person, firm or corpo- 
ration to whom the contract shall be awarded will be referred 
to as the Contractor; and the engineer employed by the Board 
will be referred to as the Engineer. 

Plans and Drawings. 

The plan, profile and cross sections on file in the office 
of the Board show the general locations, profile, details and 
dimensions. The work will be constructed in all respects ac- 
cording to the above mentioned plans, profile and cross sec- 
tions, which forms a part of these specifications. 

Any variation of location, profile, size and dimensions 
from that shown on the plans, which may be required by the 
exigencies of construction, will in all cases be determined by 
the Engineer; and the Contractor shall not, on any pretense, 
save that of the written order of the Board, deviate from the 
intent of these plans and specifications. 

On all drawings, figured dimensions are to govern in 
cases of discrepancies between scale and figures. 
Commencement of Work. 

The work embraced in these specifications shall be begun 

not later than , and carried on regularly and 

uninterruptedly, unless the Board shall otherwise direct, and 
with such force as to insure its completion within the time 
specified in the contract. The Contractor will give the Board 
ten days' notice before commencement of the work, and also 
notice that he has on hand or available the necessary material 
to uninterruptedly carry on the work to completion. 

After the work shall have been commenced, if the same 
shall be interrupted and delayed by the Contractor from any 
cause whatever,' the Board shall have the right to hire an in- 
spector or watchman and put him in charge of the road dur- 
ing the interruption, and to deduct the wages paid such em- 
ploye from amount due the Contractor. 

Orders to Be Obeyed. 

Whenever the Contractor is not present on the work 
orders will be given to the superintendents or overseers who 
may be in immediate charge thereof, and shall by them be 
Board or its duly authorized agents, in anything relating to 

(185) 



186 Concrete Roads and Pavements. 

the work or shall appear to the Board to be incompetent, dis- 
orderly or unfaithful, he shall, upon the order of the Board, 
be at once discharged, and not again employed on any part 
of the work. 

Tiling. 

If the work is to be constructed alongside a street railway 
track, the first work to be done will be the laying of a course 
of 3-inch land tile on the side of said road next to said track, 
distant four feet from and parallel with the nearest rail, and 
at the depth shown on plans. Before the filling back is per- 
mitted, the tile must be covered their entire length and one- 
half their circumference with a layer of tar paper, to keep 
sand and other material from washing through the joints. 

Each proposal must state the price per lineal foot at 
which the bidder will undertake to do the tiling as above in- 
dicated; but the Board reserves the right to reject that part 
of the proposal relating to tiling, and do that part of the 
work by day labor, and to accept that part of the proposal 
relating to roadway proper only, on those parts relating to 
roadway proper and open ditching; in either of which cases 
the work of tiling at any given point must be completed be- 
fore the work on the roadway proper is begun. 
Open Ditching. 

If the work to be constructed is not alongside a street 
rail track, an open ditch must be dug along both sides of said 
road beyond the earth shoulders, location and dimensions of 
said ditches being shown on plans. This work may be done 
either before or after the roadway proper; but if done before 
the ditches must be kept free and clear from rubbish and 
refuse during the construction of the roadway proper, and left 
in as good condition in every way as it would have been if 
done after the concreting and building of shoulders. If the 
work to be constructed is alongside a street railway track, 
then an open ditch will be dug only on the side of the work 
opposite the street railway track. 

Each proposal must state the price per lineal foot at which 
the bidder will undertake to do the open ditching as above 
indicated; but the Board reserves the right to reject that 
part of the proposal relating to open ditching and do that 
part of the work by day labor, and to accept that part of the 
proposal relating to roadway proper only or those parts relat- 
ing to roadway proper and tiling. 

Grading. 

The Contractor shall do all the excavating and filling 
necessary to bring the subgrade to the required elevation 
shown on plans and designated by grade stakes. After the 
subgrade has been prepared, and before any materials are 
drawn thereon, it shall be rolled with a steam roller weighing 
at least ten tons. Wherever soft spots occur in the subgrade 



Concrete Boads and Pavements. 18Y 

which cannot be made hard by rolling, the soft material must 
be removed and material which will pack with rolling must 
be substituted, and thereafter rolled to the required hardness. 

Cement. 

The cement to be used has been contracted for by the 

Board at per barrel, cloth sacks, delivered in carload 

lots at any railroad siding in Wayne County, on 30 days' time, 
subject to discount of Ic per barrel if paid within ten days 
after the car is placed on the siding to which originally or- 
dered. Cloth sacks will be charged at 10c each (included in 
above price) and when returned to the factory of the company 
furnishing same, freight prepaid, in good condition, subject 
to factory count and Inspection, will be credited at the same 
price as charged. 

The contractor must order and pay for the cement as per 
contract referred to, and must take care of and return to the 
factory all sacks, freight prepaid, in order to be entitled to 
the credit for same. The contract referred to is on file in 
the office of the Board, and may be seen upon request. 
Sand and Pebbles. 

The sand to be used has been contracted for by the Board 
at prices ranging .... to . . . . , and the pebbles at prices 
ranging from .... to . . . . , delivered at various sidings in 
Wayne County. The Contractor must order and pay for the 
sand and pebbles to be used on the work, and must order 
both from the same shipper, the shipper to be designated by 
the Board at the time the Contractor asks to see the specifica- 
tions. The contracts for the material are on file in the office 
of the Board and may be seen upon request. 
Concrete. 

Concrete shall consist of two parts of cement, three parts 
of sand, and six parts of pebbles, evenly and thoroughly 
mixed; parts of cement, sand and pebbles to be determined by 
measurement. 

Mixing. 

All concrete shall be mixed in mechanical batch mixers, 
which the Contractor shall furnish, of a type to be approved 
by the Board; and measurements of all material shall betaken 
in manner to be approved by the Engineer. 

Placing the Concrete in Position. 

Before placing the concrete, 2 inch x 7 inch plank shall 
be placed on edge and staked in line with the outer edge of 
the pavement, the upper edge of said plank to conform to 
the finished grade of the road. The workmen shall place the 
concrete in position in the pavement where directed, and it 
shall be well tamped. 



188 Concrete Roads and Pavements. 

Finishing the Surface. 

The Contractor shall employ at least two men whose 
special duty it shall be to use a strike board having a curva- 
ture corresponding to the crown of the road, so that the top 
can be properly stroked off. 

At night, and at any other time when the work is discon- 
tinued for a time, all work must be completed up to an ex- 
pansion joint, hereinafter provided for. In other words, no 
section of the pavement will be allowed to be left unfinished 
for a longer period than 20 minutes if work thereon has been 
started. 

In the work of placing the concrete in position, and in 
finishing the subgrade and all other work done under the 
contract, all foot and other traffic, both of employes and other- 
wise, must be kept off the top of the concrete until it has 
thoroughly set; and the Contractor must provide such bridges 
and other devices as will effectually carry out the provisions 
of this paragraph. 

Protection of Concrete After Laying. 

After the concrete is laid, and until it has thoroughly set, 
it shall be protected from the sun by a canvas or other suit- 
able covering, in a manner to be approved by the Engineer. 

When, in the judgment of the Engineer, the concrete is 
sufficiently hard to warrant, this covering shall be removed 
and the concrete covered with a layer of sand or gravel, about 
2 inches in depth, or such other device as may be approved by 
the Engineer, and sprinkled and kept damp 8 days, to prevent 
the surface of the concrete from drying out too rapidly while 
setting, which covering shall be left on the concrete for a 
period of seven days, and then removed and taken away from 
the road or otherwise disposed of in manner to be approved 
by the Engineer. 

Expansion Joints. 

To allow for expansion the pavement shall be built in 
sections 25 feet in length, and at each end of each section a 
soft steel plate 3-16 inches thick, extending the entire width 
and depth of the road shall be imbedded in the concrete and 
fastened to the section by projections from the steel or in 
some other manner satisfactory to the Board. It is hereby 
expressly stipulated that the joints furnished by the R. D. 
Baker Company, Home Bank Building, Detroit, will be satis- 
factory. Between these sections, cutting the entire depth of 
the concrete, shall be placed an asphalted felt, about Vs of 
an inch thick. 

Crossing Over Subgrade. 

Before any concrete pavement is constructed, and after 
the subgrade has been prepared, the Contractor shall provide 
sufficient planks at his own expense and place and maintain 



Concrete Roads and Pavements. 189 

crossings over said subgrade when the same is wet or muddy, 
unless he shall be excused therefrom, in writing, by the Engi- 
neer. Crossings for foot pasengers shall be placed at each 
cross street to accommodate the public. 
Shoulders. 

After the pavement is laid, earth shoulders must be built 
on each side thereof, of sufficient width to bring the total 

width of the road from berm to berm up to feet, as 

shown on plans. These shoulders must be built in layers not 
exceeding 4 inches in depth, and each layer must be well 
packed before the next layer is placed. 

When completed, the shoulders must be rolled as directed 
by the Board, with a roller to be approved by the Board; but 
such rolling will not be permitted until the concrete has thor- 
oughly hardened, and in any event not until at least 14 days 
have elapsed after the laying of the concrete opposite. 
Engineer's Stakes. 

The work to be done will be staked out by the Engineer, 
and any stakes broken or removed through carelessness of 
the Contractor or his employes will be replaced by the Engi- 
neer at a cost to the Contractor of one dollar each. The Con- 
tractor shall give 24 hours' notice when he needs the services 
of the Engineer. 

Material on Road. 

Material delivered on the road in connection with the 
work must be neatly and compactly piled along the sides in 
such manner as to cause the least inconvenience to the public 
and the adjacent property owners. Private drives and road 
crossings must be kept open as far as practicable, and planked 
when directed, to the satisfaction of the Engineer. Shade 
trees and other improvements shall be protected by the Con- 
tractor from all damage by stone or otherwise. 
Surplus Earth. 

All earth not needed for filling or shoulders or otherwise 
in connection with the work, must be disposed of by the Con- 
tractor in manner to be approved by the Engineer, at some 
point not further distant from point of origin than 1,000 feet. 
Obstructing Travel. 

Travel upon the road, and upon intersecting roads and 
alleys, shall not be inconvenienced needlessly; nor shall any 
portion of the roadway be opened up, nor shall the same be 
wholly obstructed, except as directed by the Engineer; in 
which case the Contractor shall cause plain and properly 
worded signs, "Road Closed, by Order of the Board of County 
Road Commissioners," announcing such fact, to be placed 
with proper barricades, and with other signs by day and 
lanterns by night, plainly indicating the nearest route around 



190 Concrete Bonds and Pavements. 

the obstructed portion, at the nearest cross road beyond each 
<3nd of such obstructed portion, and upon intersecting roads, 
so that travel can pass around same in the shortest and 
easiest way. 

Liabilities of Contractor. 

The Contractor must provide a watchman at each end of 
the road continuously, day and night, and also red lights by 
night, to effectively keep travel off the pavement, until re- 
lieved therefrom by the Engineer, in writing; and the former 
must assume, and will be held liable for, any and all damage 
which may arise from his neglect to do so, or from any omis- 
sions on his part. 

All loss and damage arising from the nature of the work 
to be done, or from any unforeseen or unusual obstruction or 
difficulty, which may be encountered in the prosecution of the 
work undertaken by him, or from the action of the elements,, 
shall be sustained and borne by the Contractor. 

Inspection. 

The work shall at all times be subject to inspection by 
the Board and its agents; but such inspection shall not re- 
lieve the Contractor from any obligation to perform said work 
strictly in accordance with these specifications; and the work 
not so constructed shall be removed and made good by the 
Contractor whenever so ordered prior to final acceptance, 
without reference to any previous oversight in inspection. 
Defects Before Acceptance. 

All depressions, defects and imperfections in any portion 
of the pavement, whether due to public travel, rain, snow, 
ice, frost, or other causes, before final acceptance of the work 
by the Board, shall be repaired and made good by the Con- 
tractor at his own expense. All rubbish which may accumu- 
late during and by reason of the work herein provided shall 
be removed by the Contractor as fast as the pavement is laid, 
and the streets left clean and in good condition. 
Payments. 

The Engineer will, on or about the first day of each 
calendar month during the progress of the work, make and 
deliver to the Board an estimate, showing, as nearly as he 
can approximate the same, the number of lineal feet of road- 
way that have been completed; from which estimate the 
Board will compute the amount due the Contractor on a pro 
rata basis; and, after deducting 20 per cent of the whole 
amount earned, and the sum of all previous payments, will 
draw its voucher in favor of the Contractor for the balance 
of the amount found to be due. 

When the work is completed and accepted, and final 
estimate is made, the Board will draw its voucher in payment 
of the balance due the Contractor; provided, that if, in the 



Concrete Boads and Pavements. 191 

judgment of the Board, the proper execution of its work on 
other roads requires, they may retain an amount equal to the 
state reward earned on said road until such state reward is 
paid into the Good Roads Fund of Wayne County. 
Demurrage, Overshipments, Etc. 

Inasmuch as all material must be ordered by the Con- 
tractor, and unloaded and handled by him, he will be expected 
to order only so much thereof, respectively, as is required for 
use on the work, and in such quantities as can be conveniently 
taken care of by him. Any demurrage or storage charges ac- 
cruing on any material ordered or shipped, and any additional 
freight or switching charges accruing by reason of his failure 
to give proper shipping directions as above required, and 
charges for any overshipment made, must be assumed and 
adjusted by the Contractor; and the Board reserves the right 
to hold back a sum sufficient to cover same until they are 
properly adjusted. And if it shall appear to the Board after 
a reasonable time, that the Contractor intends to disregard, 
or may be unable or unlikely to arrive at a speedy adjustment 
of any or all of such charges, the Board reserves the right 
to pay them, and deduct the amount so paid from any amount 
found due the Contractor. 

Proposals. 

All proposals must be made upon forms designed by the 
Board, and must give all the information called for or indi- 
cated by such forms; and must be on the basis of the Con- 
tractor furnishing all materials, tools, machinery, appliances 
and labor, except as herein otherwise expressly provided, 
necessary for the efficient and proper carrying on of the 
work. 

All proposals must be made on the basis of a given price 
per lineal foot, and must state separately the price for tiling, 
open ditching, and all other work (which last is designated 
herein as "roadway proper"). The Board expressly reserves 
the right to accept the proposal for a greater or less distance 
than that given in the description of the road above, based 
upon the amount of money available for use on the road, prob- 
able cost of inspection, and other considerations. 

All proposals must be sealed; addressed to Wm. F- Butler. 

Chairman; endorsed, "Proposal to build Road"; 

and accompanied by a certified check on some solvent bank, 

payable to Wayne County, in the sum of Dollars; 

which check of the successful bidder is to be forfeited as 
liquidated damages and placed to the credit of the Wayne 
County Good Roads Fund in case such bidder shall fail to 
execute a contract to construct the pavement in accordance 
with these specifications and his proposal, and furnish the 
bonds herein required, within five days after presentation of 
draft of same. 



192 Concrete Roads and, Pavements. 

Proposals will be received up to 2 p. m., standard time, of 

1912, and not later, and then publicly opened. 

The right to accept or reject any or all proposals is expressly 
reserved. 

Engineer's Estimate. 

A copy of the Engineer's estimate of the quantities of 
materials required is attached hereto, marked Exhibit A, The 
quantities given are the result of calculation, but are to be 
considered only as approximate. The Contractor is expected 
to satisfy himself as to the nature, character and quantity of 
the labor and materials required by a personal examination 
of the work contemplated. 

Assignment of Contract or iVIoneys. 

The Contractor shall not assign nor transfer the contract, 
nor sublet any portion of the work embraced in it, nor give 
an order for the payment of any moneys due or to become 
due by virtue of the contract or of work done under it, with- 
out the consent of the Board, in writing, being first obtained. 
Work and Forfeits. 

If the Contractor shall fail to complete the work wtihin 
the time specified in the contract, a sum sufficient to pay for 
inspection and other expenses of the Board, not, however, 
exceeding in all fifteen dollars per day for each and every day 
thereafter (Sundays and legal holidays included) shall be de- 
ducted from the amount due under the contract, as stipulated 
damages for failure to complete the work within the time 
specified therein; provided, however, that all days on which 
work is suspended by order of the Board or Engineer shall 
be deducted from overtime, if any there be. 
Bills for Extras. 

No bills for extras, for labor or material furnished, shall 
be considered or allowed under any circumstances after the 
final estimate has been allowed and the pavement duly ac- 
cepted; nor will any bills for extras, labor or material fur- 
nished, be considered or allowed unless said extra work or 
materials furnished shall have been agreed upon in writing, 
stating price in detail or aggregate, signed by a majority of 
the Board and the Contractor, before such extra work is done 
or materials furnished; and upon completion of such extra 
work, the Contractor shall immediately file with the Board a 
statement or bill of items, in duplicate, showing the full 
amount of his claim for work or materials furnished under the 
agreement; otherwise he shall be deemed to have waived his 
claim. 

Bonds of Contractor. 

The Contractor will be required to execute and furnish, 
contemporaneously with the execution of the contract, a 



Concrete Roads and Pavements. 193 

surety bond in the sum of Dollars, conditioned 

on the faithful performance of the contract, to indemnify and 
save harmless the Board from all suits and actions of any 
name or description brought against them on account of any 
act or omission of the Contractor or his agents. 

Any change made in the plans, specifications, agreements 
or quantities, whether made with or without the consent of 
the surety company, shall in no way vitiate said bond; the 
right of the Board to make such changes as it sees fit being 
expressly reserved. 

The Contractor must further agree that so much of the 
money as may be due him under and by virtue of the contract 
and work performed thereunder as shall by the Board be 
deemed prudent, may be retained by them until all suits and 
claims for damages as aforesaid, shall have been settled, 
and satisfactory evidence to that effect furnished to the 
Board. 

The Contractor shall also furnish bond in the penal sum 

of Dollars, provided for by sections 10743 and 10744 

of the Compiled Laws of 1897, and amendments thereto. 

The Contractor must also furnish surety bonds in the sum 

of Dollars, conditions upon the maintenance and 

proper repair of said road for a period of two years from and 
after the date of its completion. 



APPENDIX C. 



MASON CITY SPECIFICATIONS. 

1. All streets prior to laying any pavement thereon, 
shall be graded so that the pavement will be at the estab- 
lished grade when completed. After excavating to sub-grade, 
unless the engineer deem the natural ground a proper foun- 
dation, excavation shall be continued until solid ground is 
reached, and then re-filled to sub-grade with sand, gravel or 
broken stone. 

2. The contractor shall be required to remove, at his 
own expense, all obstructions, such as trees, old blocks, 
debris, etc. 

3. All excavated material, gutter stones, planks, mac- 
adam, crossing stones, old curbs, surplus earth, etc., shall be 
the property of the city and be deposited by the contractor 
in such place and manner as shall be directed by the engineer, 
the distance not to exceed 3,000 feet. No plowing will be 
allowed within 3 inches of the bottom of the foundation. 

4. When the street shall have been graded and shaped 
to its proper form, it shall be thoroughly rolled with a ten- 
ton roller to a thoroughly compact surface. If the ground is 
wet, sand or gravel is to be put on before rolling. 

5. Any depression descovered after this rolling, shall 
be filled to sub-grade, and this repeated until a road-bed per- 
fect as to grade and form shall have been made. 

6. When the use of the roller is impracticable, the foun- 
dation must be thoroughly puddled and rammed until com- 
pacted to the satisfaction of the engineer. 

7. Upon the roadway thus formed, will be laid a founda- 
tion of Portland cement concrete five (5) inches thick, to be 
made as follows: One part by measure of Portland cement: 
2 parts by measure of clean, sharp sand, and 5 parts by meas- 
ure of broken stone. 

8. The sand and cement shall be thoroughly mixed into 
mortar, at the proper consistency, with a batch mixer ap- 
proved by the engineer. Broken stone, thoroughly cleaned 
of dirt, drenched with water, but containing no loose water 
in the heap, shall then be added to the mortar in the proper 
proportion. The concrete will then be turned and mixed until 
each fragment is thoroughly coated with mortar. 

9. A strictly wet mixture will be required. 

10- The concrete thus prepared shall be placed immedi- 
ately in the work. It shall be spread and thoroughly com- 
pacted until free mortar appears on the surface, which shall 



Concrete Roads and Pavements. 195 

be made smooth and parallel to the surface of the finished 
pavement. The whole operation of mixing and laying each 
batch of concrete shall be performed in an expeditious and 
workmanlike manner and be entirely completed before the 
cement has begun to set. 

11. No re-tempering of concrete will be permitted, and 
concrete in which the mortar has begun to set will be re- 
jected. 

12. The thickness of this concrete to be five inches after 
the same has been compacted. 

13. Extreme care should be taken that the sub-grade is 
kept moist while this concrete is being put in place. 

14. No concrete shall be laid when the temperature at 
any time during the day or night falls below 35° above zero, 
Fahrenheit. 

15. Upon the concrete heretofore specified shall be im- 
mediately laid a wearing surface 2 inches in thickness to 
be made as follows: One part by measure of Portland cement, 
2 parts by measure of coarse, clean, sharp sand. The sand 
and cement shall be thoroughly mixed into mortar of the 
proper consistency with an approved batch mixer. 

16. The mortar thus mixed will be immediately laid 
upon the concrete heretofore specified. 

17. Before this mortar has begun to set, it will be fin- 
ished off to a smooth surface with a wood float, and before 
it has completely hardened, it shall be roughened by brush- 
ing with a stiff vegetable brush or broom. 

18. All forms for expansion and contraction joints shall 
be made of iron or steel in the form of a template, cut to 
the desired shape of the street, according to the plans, and 
of sufficient strength to resist springing out of shape. All 
mortar and dirt shall be removed from the forms that have 
been previously used. The forms shall be well staked to the 
established lines and grades. 

19. Contraction joints shall be made entirely through 
the pavement every 12 1^ feet at right angles with the street 
except at expansion joints. The edges of all unprotected 
expansion joints and all contraction joints shall be rounded 
to a radius of ^2 inch, with proper tools. 

20. The sides of all expansion joints that are at right 
angles with the curb lines, shall be protected by a protec- 
tion plate to be of soft steel one-quarter (i/4) of an inch in 
thickness, 2^^ inches in width, a shear member to be punched 
from the side of the plate, and bent at right angles to the 
same. Shear member to be 6 inches long and % of an inch 
In width, spaced 10 inches center to center. Protection plates- 
shall be in sections not less than feet in length, and 

cut to the desired crown of the street. 



196 Concrete Boads and Pavements. 



21. The curvature and cross-sections of the pavement to 
be made according to the plans governing the same. 

22. The cement used in the work will be submitted to 
the tests approved and recommended by the American So- 
ciety of Civil Engineers, which it must stand to the satisfac- 
tion of the engineer. 

23. All Portland cement used in the work shall be Mason 
City Portland cement, or other Portland cement equally as 
good, which shall be protected from the weather, free from 
exposure to air slacking and from moisture, until used. 

24- The sand shall be clean, sharp sand. 

25. The stone used for the concrete shall be of the best 
quality of hard limestone, or other stone equally as good, 
and shall be broken to such a size that the fragments shall 
not be larger than will pass through a li/^-inch ring and not 
smaller than a hazel nut. It shall be free from dust, dirt, 
loam or other objectionable material and shall be screened 
when necessary over a i/^-inch screen to eliminate dust and 
small particles. 

26. An expansion joint 1 inch in width shall be left next 
to the curb on each side of the street or alley, also an ex- 
pansion joint ^ inch in width will be left every 37 1/^ feet 
across said pavement at right angles to the curbs. Said ex- 
pansion joints are to be filled with an asphalt paving filler 
of proper quality and consistency approved by the engineer. 
It will be applied while heated to a temperature of about 400° 
Fahrenheit, and shall be so applied that said expansion joints 
shall be thoroughly filled clear to the top of surface of said 
pavement. 

27. Care shall be taken to obtain a surface free of 
ridges, at expansion joints, and depressions or unevenness in 
the surface, that will detract from its appearance, or cause 
water to lay on the pavement. 

28. Any sections having such inferior surface will be re- 
jected, and shall be rebuilt by contractor at his own expense. 

29. Care shall be taken to make the expansion joints in 
such a manner that they are practically the same width 
throughout their depth. 

30. Extreme care must be exercised in removing tem- 
plates or divisions used to make expansion joints; the break- 
ing out of any portion of the pavement, in removing such 
templates and forms, will not be tolerated, and such dam- 
aged portions of the work shall be torn out and replaced in 
good condition by the contractor at his own expense. 

31. The contractor shall keep pavement sprinkled con- 
stantly and kept wet once a day for one week after it is laid 
or longer if deemed necessary by the engineer. 

32. The contractor shall keep the street closed to traffic 
at least two weeks after the completion of same. 



APPEXDIX 1). 

THE SPECIFICATIONS OF THE ILLINOIS HIGHWAY 

COMMISSION FOR CONCRETE ROAD 

CONSTRUCTION. 

Concrete Materials. 

Cement. — Some standard brand of Portland cement shall 
be used which has been in practical use on public works and 
shall have proved satisfactory therein. No brand of cement 
shall be used which the engineer deems unfit for the work, 
nor shall any cement be used which fails to give satisfactory 
results according to the standard methods of testing as pro- 
vided by the American Society for Testing Materials. The 
contractor shall provide sufficient means to protect the 
cement against dampness, and no cement shall be used which 
has become caked. 

The contractor shall notify the engineer in writing what 
brand or brands he intends to use, and before ordering the 
cement shall receive the written approval of the engineer as 
to the brand selected. It is understood that such approval 
merely covers the selection of the brand; that the cement 
itself may be rejected if it fails to meet the requirements 
herein specified. 

Coarse Aggregate. — The coarse aggregate shall consist 
of clean, hard, sound flint or other hard siliceous pebbles, 
having a reasonably uniform gradation from a size which will 
pass through a 1-inch screen to a size that is retained on a 
%-inch screen, and no gravel composed in part of slate, shale, 
disintegrated limestone, or other equally soft stone, can be 
used. Crushed granite or trap rock, graded to the size pro- 
vided above, may be used. Crushed limestone, graded to the 
size specified above, may be used only upon the approval of 
the engineer. 

Fine Aggregate. — The fine aggregate shall consist of 
clean, sharp quartz grains, and shall not contain over 2 per 
cent of clay or loam. The fine aggregate shall be reasonably 
uniformly graded from a size which will pass through a %- 
inch screen down. Sand containing disintegrated shale, slate 
or limestone shall not be used. 

Grading oT Aggregate. 

The specification that the coarse and fine aggregates 
must be reasonably well graded shall be interpreted to mean 
that the percentages of the aggregates passing screens of 

(197) 



198 Concrete Roads and Pavements. 

various sizes shall be within the limits given in the follow- 
ing tables: 

Table of Gradation of Coarse Aggregate. 

Allowable limits of 
Size of screen. Percentage passing through. 

1-inch square mesh 100 

^-inch square mesh Not less than 45 nor more than 60 

Table of Gradation of Fine Aggregate. 
Size of screen. Allowable limits of 

Percentage passing through. 

%-inch square mesh 100 

ife-inch square mesh Not less than 65 nor more than 85 

If the contractor desires to use aggregate which is not 
graded in accordance with the table, he must submit a sam- 
ple of 50 pounds of such material to the Illinois Highway- 
Commission, Springfield, 111., one week prior to the date of 
letting of this contract. His sample of aggregate will be 
analyzed and, if found suitable, its use will be approved in 
writing and the amount of cement that must be used with 
such aggregate will be stated. The aggregate used in the 
construction work must then be graded in accordance with 
the sample submitted, and must be of the same kind and 
quality as the sample, and the amount of cement used must 
be the quantity required by the engineer in accordance with 
this paragraph instead of the amount provided in paragraph 
32. [Proportions for concrete.] 

Use of Gravel. 
The use of gravel made up of a mixture of the coarse and 
fine aggregates described above will not be permitted. If the 
contractor wishes to use such material, he must screen it to 
the sizes specified above before proportioning the aggregate 
for mixing. 

Concrete Mixer. 
The concrete mixer used on the work provided for herein 
shall be a batch mixer of a type approved by the engineer. 
The concrete shall receive at least four complete turns of 
the drum before being discharged, and if, in the opinion of 
the inspector, a greater amount of mixing is required, this 
number of turns shall be increased until a thoroughly mixed 
concrete is secured. 

Proportions for Concrete. 
The concrete for the work provided for herein shall con- 
sist of 1 part of cement, 2 parts of fine aggregate, and 3^^ 
parts of coarse aggregate. The aggregate shall be placed in 
the mixer in such manner as to insure that a uniform amount 
of each class of aggregate is used in each batch of concrete; 
and the method of measuring the aggregate, whether in wheel- 



Cono'cie Roads and Paconents. 199 

barrows, or otherwise, shall be approved by the inspector, 1 
sack of cement to be considered as 0.95 cubic feet, and all 
measurements to be by volume. 

Water. 

The water used in mixing the concrete shall be clean. 
Size and Kind of Roller. 

Wherever it is provided herein that rolling shall be done 
on the roadbed or macadam shoulders, a three-wheel self- 
propelling roller, weighing not less than ten nor more than 
twelve tons shall be used. 

Roadbed. 

The roadbed will be considered as that portion of the 
road upon which the concrete roadway and macadam shoulder 
are placed. The roadbed shall consist of the natural earth 
which has been brought to the proper elevation and cross 
section and rolled until firm and hard. If sandy or other soil 
is encountered which will not compact readily under the 
roller, a small amount of clay or loam shall be added so as 
to secure a firm, hard surface after rolling. The roadbed 
shall be thoroughly saturated with water immediately before 
concrete is placed. 

Shoulders and Side Roads. 

After the completion of the concrete roadway and ma- 
cadam shoulders, the side roads are to be shaped in accord- 
ance with the cross section shown on the plans and shall be 
rolled, care being taken not to allow the roller on the edge 
of the concrete roadway. Upon completion, the cross slope 
of the concrete roadway, macadam shoulders, earth side roads 
and ditches shall be as shown on the plans. 

Thickness of Concrete Roadway. 

The concrete roadway shall have, after completion, the 
thickness shown on the plans. If a greater thickess is laid 
than that shown on the plans, no extra compensation will be 
made therefor. 

Under Drains. 

An under drain 8 inches wide and 6 inches deep shall be 
constructed under each of the concrete roadway edges, the 
entire width of the drain being under the pavement. This 
under drain shall be filled with broken stone or coarse ag- 
gregate before the concrete is placed. At the end of each 
expansion joint or at intervals of not to exceed 50 feet, blind 
cross drains, not less than 8 inches wide, shall be con- 
structed from the longitudinal drains before mentioned, to 
the gutter. These cross drains shall be of such a depth as 
to drain readily from the longitudinal drains to the gutter, 
and shall be filled with at least 6 inches of crushed stone or 
coarse aggregate, and then covered with earth, except that 



200 Concrete Roads and Pavements. 

such part of the cross drain as lies under the macadam 
shoulder shall be filled with stone when the shoulder is con- 
structed. The longitudinal and cross drains shall be com- 
pleted before the concrete roadway is constructed. 
Side Forms. 

The concrete roadway shall be placed between side forms 
of 2-inch plank. The side form plank shall be of a width 
equal to the thickness of the pavement at the edge. The 
side form planking shall be accurately set to the alignment 
and grade of the pavement, and shall be held securely in 
place by adequate stakes and bracing. Intermediate longi- 
tudinal form boards will not be permitted between the side 
forms to support the templet. 

Placing Concrete Roadway. 

The concrete for the roadway shall be placed between the 
plank forms before described, the entire thickness of the con- 
crete being placed at one time. After the concrete has been 
deposited between the forms, it shall be raked and tamped 
until the mortar flushes to the top, and the concrete shall be 
placed in such quantity that there will be a slight excess 
between the forms. The surface of the roadway shall then 
be shaped to conform to that which is shown on the plans by 
striking off with a templet cut to the proper shape. This 
templet shall be drawn along the forms, and shall be held 
securely against the top of the forms, and shall be moved 
with a combined longitudinal and crosswise motion which 
will prevent dragging the larger particles of the aggregate 
and marring the surface. 

Finisliing Surface of Concrete Roadway. 

After the surface of the concrete roadway has been 
struck off to the proper cross section, it shall be finished with 
wood fioats. The wood floats shall be used only to flush mor- 
tar to the porous places in the surface, and great care must 
be taken not to rub hollow places in the surface. The wood 
float finish shall be made as soon after the concrete has been 
deposited as possible, and in no case shall the finishing be 
delayed until the concrete has taken a set. 
Covering Concrete Roadway. 

After the concrete roadway has been finished as above 
described, the roadway shall be covered with suitable canvas 
as soon as this can be done without marring the surface, 
which shall be kept wet, and as soon as the concrete sets 
sufficiently, the canvas shall be removed and the concrete 
covered with earth. The earth covering shall be put on at 
least 1 inch thick and shall be kept constantly wet for two 
weeks. The roadway shall be kept close to traffic for two 
weeks, or, if in the opinion of the engineer, the weather con- 



Concrete Roads and Pavements. 201 

ditions make it advisable, the roadway shall be kept closed to 
traffic a longer period of time. 

Expansion Joints. 

Expansion joints shall be provided and spaced as shown 
on the plans. The expansion joints shall be set at an angle 
of 60 degrees with the center line of the roadway and shall 
be of the type shown on the plans. The expansion joints 
shall be constructed in such manner as to Insure that the 
metal plates, creosoted blocks, or other device provided for 
the joints, shall conform to the cross section provided for the 
roadway; and great care must be exercised in placing these 
joints to insure that there will be neither a depression nor 
a raised place at the joint. 

Cleaning Finished Pavement. 

When the concrete roadway has been completed for a 
sufficient length of time to permit a proper setting of the 
concrete, it shall be cleaned and then opened to traffic. 
Beveling Edges. 

If the plans shall provide that the edge of the concrete 
shall be beveled, then the plank forms shall be removed 
from the edge of the roadway before the concrete takes its 
final set, and the edge of the pavement shall be cut off by 
means of a shovel or other suitable tool so as to give the 
shape shown on the plans. 

Macadam Shoulders. 

The macadam shoulders when completed shall be of the 
width and thickness shown on the plans. The stone for the 
macadam shoulders shall be deposited, spread and rolled at 
least twice over, and then covered with screenings or gravel, 
sprinkled and rolled. When completed the macadam shoulder 
shall be true to shape and shall be ^2 inch above the concrete 
where it joins the concrete roadway. 

Trimming Sides of Road. 

The slopes on cuts and fills shall be neatly trimmed to 
the slopes shown on the plans, and all detritus and surplus 
materials left after completion of the work shall be removed 
from the road. 



APPEIS^DIX E. 

SPECIFICATIONS FOR BLOME GRANITOID PAVEMENT. 
Preparation of Sub-Grade. 

The sub-grade shall conform exactly to the lines and ele- 
vations shown on the plans or profiles or as furnished to the 
contractor by the engineer in charge or under the direction 
of the engineer. The street shall be graded (excavated or" 
filled as the case may be) to sub-grade, as specified and pro- 
vided for in the general specifications, in such a manner as 
to provide a solid foundation for the pavement and all slopes, 
contours and other shaping required in the pavement shall 
be formed and provided for in said sub-grade, so that the 
foundation and pavement hereinafter specified shall be of 
uniformly the same thickness throughout. 

The contractor will bid with the understanding that the 
sub-grade is to be prepared in such a manner as to support 
the pavement permanently and retain the original grades. 
Any spongy material, vegetable matter or any material un- 
suitable as a foundation shall be removed and the spaces re- 
filled with proper material, tamped or rolled until compact. 
This clause shall not be waived on account of openings made 
in the street by any corporation or individual prior to the 
laying of the pavement. 

Materials. 

The cement used for this work to be a standard brand of 
Portland cement complying with all the requirements of the 
American Society for Testing Materials. All cement to be 
delivered on the work in approved packages bearing name, 
brand or stamp of the manufacturer, and 94 pounds net of 
cement shall be considered as 1 cubic foot. All cement to 
be carefully protected from the weather until used. 

The sand shall be free from clay, loam, vegetable matter 
and dust. The grains shall vary in size from %-inch down 
to the finest and so graded that the voids, as determined by 
saturation shall not exceed 33 per cent of the volume. No 
wind drifted sand to be used. 

The stone used in making the concrete shall be of the 
best quality of limestone, trap rock or other hard stone, or 
of gravel of size so as to measure not more than 2i/^ inches, 
and in the event of stone being used same shall not measure 
under ^4 inch in dimension. 

Clean, acceptable, pit-run gravel, from which all organic 
matter and dust has been eliminated, may be used for the 

(202) 



Concrete Roads and Pavements. 203 

concrete bed or lower course of the pavement. The sizes 
of sand grains and stone in pit gravel and the proportions 
of fine and coarse aggregate shall correspond to specifications 
for sand and stone, and deficiencies shall be made up by the 
addition of sand or crushed stone or gravel. 

When delivered on the street these materials shall be 
placed in such a manner as to be kept clean until used. 
Mixing and Laying of Concrete, and Formation of the Blome 
Company Granitoid Blocking. 

The concrete bed or foundation and the surfacing here- 
inafter specified shall be constructed and manipulated in ac- 
cordance with the Blome Company patents and processes, 
utilizing materials mixed in the proportions and laid as here- 
inbefore specified. 

Upon the sub-grade and foundation prepared as herein- 
before specified the Granitoid Concrete Pavement shall be 
laid, consisting of 6% inches of concrete at the center of 
street and gradually decreased to 4i^ inches at the curbs or 
outer sides of pavement, and on same shall be placed the 
Granitoid surface blocking of uniform thickness of ly^ inches. 

Whenever there are street car tracks on the street pro- 
posed to be paved, the thickness of the concrete bed shall be 
equal to the average thickness of the concrete above specified 
uniformly at all points of the areas to be paved. 

The concrete shall be composed of 1 part of Portland 
cement, 3 parts of sand and 4 parts of limestone, trap rock 
or other hard stone or clean gravel. These materials to com- 
ply with the requirements hereinbefore set forth and shall 
be mixed by an approved mixing machine, suitable for the 
purpose, approved by the engineer in charge, each batch 
being turned at least 5 times before being removed from 
the mixer. 

The concrete shall be thoroughly tamped into place and 
shall be of the thickness specified, after having been com- 
pacted and shall be carefully rammed into sections separated 
by expansion joints, all as per the Blome Company patents, 
and the said concrete shall follow the slopes of the finished 
pavement so that the surface blocking is, and shall be, of 
uniform thickness at all points. 

Granitoid Blocking. 

After the concrete has been placed and before it has 
begun to set, there shall be immediately deposited thereon 
the Granitoid Blocking, which shall be l^/^ inches in thickness, 
to be composed of 2 parts of approved Portland cement and 3 
parts of crushed granite, trap rock, gravel, hard stone or 
other similarly hard material, which shall be screened with 
the dust removed therefrom, utilizing the following propor- 
tions of this material: 

Substantially 50 per cent to be what is known as %-inch 



204 Concrete Roads and Pavements. 



size, 25 per cent of i/4-mch size, and 25 percent of %-inch 
size, with all finer particles removed. This material shall 
be thoroughly mixed with approved cement and after being 
wetted to the proper consistency and deposited on the con- 
crete, shall be worked into brick shapes of approximately 4^/^ 
inches by 9 inches, with rectangular surface similar to pav- 
ing blocks, all as per special method and utilizing the groov- 
ing apparatus as employed under the Blome Company patents. 

The pavement shall be sloped in the manner required by 
the engineer in charge and in event any part or parts of the 
pavement, when completed, where slopes, contours, etc., have 
not been carried out in a true manner, then, under these 
specifications, the contractor will be required to take up such 
part or parts, and replace same to the proper level, without 
expense. 

Expansion Joints. 

The contractor shall provide for and form expansion 
joints across the pavement at such intervals as may be nec- 
essary, and, where advisable, also along the sides at the 
curbs or gutters, which expansion joints shall extend entirely 
through the surface blocking and the concrete and shall be 
filled with a composition especially prepared for the purpose 
in accordance with the Blome Company patents. These ex- 
pansion joints shall be constructed in an extremely careful 
manner, under specific direction of the engineer in charge. 
Patents, Trademarks, Etc. 

All fees for any patent inventions, materials, articles or 
arrangement or other apparatus that may be used upon or be 
in any way connected with the construction, erection or main- 
tenance of the work or any part thereof embraced in the con- 
tract or the specifications, shall be included in the prices stipu- 
lated in the contract for said work and the contractor must 
show conclusively that he has a license permitting and giving 
him the right to use the patented inventions, materials, articles 
or arrangement or other apparatus necessary for the construc- 
tion of the pavement under these specifications and the price 
stipulated in the contract for said work must include such 
cost and the contractor must protect and hold harmless the 
city against any and all demands for such fees or claims. 

Blome Company trademark plates will be provided show- 
ing the dates of pavement patents, etc., together with trade- 
marks, which plates shall be set by the contractor at such 
locations as may be designated by the Blome Company. 



APPE^S^DIX F. 



SPECIFICATIONS FOR BLOME GRANOCRETE PAVEMENT 
Preparation of Sub-Grade. 

The sub-grade shall conform exactly to the lines and 
elevations shown on the plans or profiles or as furnished to 
the contractor by the engineer in charge or under the direc- 
tion of the engineer. The street shall be graded (excavated 
or filled as the case may be) to sub-grade, as specified and 
provided for in the general specifications, in such a manner 
as to provide a solid foundation for the pavement and all 
slopes, contours and other shaping required in the pavement 
shall be formed and provided for in said sub-grade, so that the 
foundation and pavement hereinafter specified shall be of 
uniformly the same thickness throughout. 

The contractor will bid with the understanding that the 
sub-grade is to be prepared in such a manner as to support 
the pavement permanently and retain the original grades. 
Any spongy material, vegetable matter or any material un- 
suitable as a foundation shall be removed and the spaces 
refilled with proper material, tamped or rolled until compact. 
This clause shall not be waived on account of openings made 
in the street by any corporation or individual prior to the 
laying of the pavement. 

Materials. 

The cement used for this work to be a standard brand of 
Portland cement complying with all the requirements of the 
American Society for Testing Materials. All cement to be 
delivered on the work in approved packages bearing name, 
brand or stamp of the manufacturer, and 94 pounds net of 
cement shall be considered as 1 cubic foot. All cement to 
be carefully protected from the weather until used. 

The sand shall be free from clay, loam, vegetable matter 
and dust. The grains shall vary in size from Vk . inch down 
to the finest, and so graded that the voids, as determined by 
saturation shall not exceed 33 per cent of the volume. No 
wind drifted sand to be used. 

The crushed stone or gravel used in making the con- 
crete, shall be of good quality of limestone, trap rock or other 
hard stone, or of gravel of size so as to measure no more 
than 2y2 inches, and then graded to the sizes hereinafter 
mentioned. 

Clean, acceptable, pit-run gravel, from which all organic 

(205) 



206 Concrete Roads and Pavements. 

matter and dust have been eliminated, may be used for the 
foundation course of the concrete. The sizes of sand grains 
and stone in pit gravel and the proportions of fine and coarse 
aggregate shall correspond to specifications for sand and 
stone, and deficiencies shall be made up by the addition of 
sand or crushed stone or gravel. 

When delivered on the street, these materials shall be 
placed in such a manner as to be kept clean until used. 
Manner of Construction of Granocrete. 

The Granocrete Pavement shall be 7 inches in thickness 
at the center of street or roadways, and decreased gradually 
to 5 inches in thickness at the curbs or outer sides of the 
pavement after having been made compact. 

Upon the sub-grade, prepared as hereinbefore specified 
shall be deposited concrete composed of 1 part of Portland 
cement and 8 parts of an aggregate consisting of approxi- 
mately 50 per cent of broken stone or gravel with particles 
below 1/^ inch eliminated, 15 per cent of i^-inch stone or 
gravel with the dust removed, and 35 per cent of clean, tor- 
pedo sand. 

This selection of sizes of ingredients is made in order 
to produce a mass which will have sufficient voids or un- 
occupied spaces to receive enough of the material consti- 
tuting the top wearing surface or layer, hereinafter described, 
to secure a firm union between the two, whereby the top 
surface is effectively anchored to this foundation. 

These materials shall be mixed by an approved mixing 
machine suitable for the purpose, approved by the engineer 
in charge, each batch being turned at least 5 times before 
being removed from the mixer. 

The concrete shall be thoroughly tamped into place and 
to be of the thickness above specified after being compacted, 
carefully rammed into sections, separated by expansion joints, 
all as per Blome Company patents and the said concrete shall 
follow the slopes of the finished pavement so that the surfac- 
ing is and shall be of uniform thickness at all points. 
Surfacing. 

After the concrete has been placed, and before it has 
begun to set, there shall be immediately deposited thereon 
the surfacing which shall consist of 1 part of Portland cement, 
1 part of coarse, sharp sand, and 1 part of a mass composed 
of hard broken stone, conglomerate or gravel of sizes herein- 
after mentioned. 

The composition of the stone or gravel in the surfacing 
shall be substantially as follows: 

Twenty-five per cent of the stone or gravel in the surfac- 
ing shall be i/4-inch size; 50 per cent shall be of %-inch size, 
and 25 per cent shall be of i/^-inch size, having in all instances 
the finer particles eliminated. 



Concrete Bonds and Pavements. 20' 



The surfacing matevial shall be thoroughly mixed with 
approved cement and, after having been wetted to the proper 
consistency, shall be deposited on the concrete and floated 
in a manner so as to thoroughly compact all of the in- 
gredients. 

The surfacing shall be 1 inch in thickness after having 
been compacted. The top stratum when compacted, enters 
the voids of the concrete sufficiently to obtain a firm 
anchorage thereto, and it is to be understood that definite 
quantities of material hereinbefore mentioned are employed 
in the surfacing to protect the sand particles or grain from 
the effects of travel. 

The pavement shall be sloped in the manner as required 
by the engineer in charge, and in the event there should be 
any part of the pavement, when completed, where slopes, 
contours, etc., have not been carried out in a true manner, 
then under these specifications, the contractor will be re- 
quired to take up such part or parts and replace same to the 
proper level without expense. 

Expansion Joints. 

The contractor shall provide for and form expansion 
joints across the pavement at such intervals as may be nec- 
essary, and, where advisable, also along the sides at the curbs 
or gutters, which expansion joints shall extend entirely 
through the surfacing and concrete, and shall be filled with 
a composition especially prepared for the purpose in accord- 
ance with the Blome Company patents. These expansion 
joints shall be constructed in an extremely careful manner, 
under specific direction of the engineer in charge. 
Patents, Trademarks, Etc. 

All fees for any patent inventions, materials, articles or 
arrangement or other apparatus that may be used upon or 
be in any way connected with the construction, erection or 
maintenance of the work or any part thereof embraced in the 
contract or the specifications, shall be included in the prices 
stipulated in the contract for said work and the contractor 
must show conclusively that he has a license permitting and 
giving him the right to use the patented inventions, materials, 
articles or arrangement or other apparatus necessary for the 
construction of the pavement under these specifications and 
the price stipulated in the contract for said work must in- 
clude such cost and the contractor must protect and hold 
harmless the city against any and all demands for such fees 
or claims. 

Blome Company trademark plates will be provided show- 
ing the dates of pavement patents, etc., together with trade- 
marks, which plates shall be set by the contractor at such 
locations as may be designated by the Blome Company. 



APPENDIX G. 

SPECIFICATIONS FOR BITUSTONE PAVEMENT. 

Excavation. 

Excavation shall be paid for at the price bid per cubic 
yard. The portion of the roadway to be improved shall be 
excavated or filled to the necessary depth below the estab- 
lished grade of the finished roadway to provide for the thick- 
ness of 5 inches Bitustone pavement. The sub-grade shall 
be rolled with a steam roller until its surface is solid, and 
approximately parallel to the proposed surface of the finished 
roadway. All excavated material shall be disposed of by the 
contractor. 

Bottom Course of Pavement. 

The bottom course of the pavement shall be laid 4 inches 
thick upon the previously rolled sub-grade and shall be com- 
posed of a Portland cement concrete mixed in the proportions 
of 1 part cement, 3 parts sand or crusher screenings, and 6 
parts crushed stone or gravel, slag, broken brick, oyster shells 
or other mineral aggregate suitable for making concrete. The 
material used in this concrete shall be of a quality usual in 
such construction. 

Bonding Course. 

Upon the bottom course of the pavement, and while the 
same is still in a wet and plastic condition, shall be spread 
and leveled, either by tamping or rolling with a light roller, 
1 inch of the Porous Bonding Course composed of hard, dur- 
able aggregate of approximately uniform size, passing screen 
openings 1 inch in diameter, and remaining on screen open- 
ings Vz inch in diameter, mixed with Portland cement in the 
proportions of 6 parts of the stone and 1 part of Portland 
cement. This mixture shall not be sufficiently wet to wash 
the cement to the bottom of the stone, and must be of such 
consistency as to insure the coating of each individual stone 
with a thin coating of pure Portland cement, which shall be 
stiff enough so as not to be displaced in the subsequent 
manipulation of grading and tamping. The Bonding Course 
when finished shall produce a surface in which the coated 
stones are firmly held together at their points of contact. 
The Bonding Course shall be kept free from dirt and other 
extraneous matter, and shall be firmly embedded in the con- 
crete bottom course. 

(20,S) 



Concrete Roads and Pavements. 209 

Filler. 

After the Bonding Course has become dry, there shall be 
poured upon it and into it sufficient Double Bond Asphaltic 
Filler to penetrate into the voids in the bonding course and 
leave a slight excess on the surface, enough excess to fill the 
superficial voids between the projecting stones, and provide 
a continuous coating of the Double Bond Filler on the surface. 
Surface Finish. 

While the filler is still hot and plastic there shall be 
scattered over it a thin layer of crusher screenings which 
will pass one-fourth (14) inch screen openings. 



APPEIS^DIX H. 

DETAIL SPECIFICATIONS FOR DOLARWAY PAVEMENT. 

1. All streets, prior to laying the pavement thereon, shall 
be graded as directed by the engineer. After excavating the 
sub-grade, unless the engineer deems the natural ground a 
proper foundation, excavation shall be continued until solid 
ground is reached and then refilled to sub-grade with sand, 
cinders, gravel or broken stone. 

2. When the sub-grade shall have been formed and prop- 
erly shaped, it shall be rolled with a roller weighing not less 
than ten tons, to a thoroughly compact surface. If the rolling 
develops wet or soft spots, they must be filled with dry 
cinders, sand or gravel. 

3. Any depression discovered after rolling shall be filled 
to sub-grade, re-rolled, and this operation repeated until a 
roadbed perfect as to grade and form shall have been made. 

4. When the use of a roller is impracticable, the founda- 
tion must be thoroughly puddled and rammed until com- 
pacted to the satisfaction of the engineer. 

5. Upon the sub-grade thus formed shall be placed a 
layer of Portland cement , concrete .... inches thick, of the 

following proportions: parts by volume of Portland 

cement; parts of clean sharp sand and parts 

of broken stone or clean gravel. 

Within twenty (20) minutes after the concrete is laid it 
shall be struck off with a template approved by the engineer, 
and as soon thereafter as practicable shall be fioated suf- 
ficiently to bring the finer particles to the top so as to pro- 
duce a smooth, uniform surface. 

The concrete shall be kept wet, if directed by the engi- 
neer, for a period of seven days. 

6. If gravel is used for concrete, it must be free from 
clay or other injurious material and shall contain no stone 
over two inches in diameter. 

Care must be taken, if the gravel is not screened, that the 
ratio of the sand to the stone in its composition shall not ex- 
ceed the above specifications for proportion of materials. 

7. If broken stone is used for concrete, it shall be of the 
best quality of limestone, or other stone equally good, and 
shall be broken to such size that no fragment shall be larger 
than will pass through a 2-inch ring, nor smaller than i/^ inch 
in its greatest dimension. It shall be clean and free from all 
foreign matter and shall be uniformly graded. 

8. The cement used in the work will be submitted to the 
tests approved and recommended by the American Society 
for Testing Materials, and any cement failing to comply with 

(210) 



Concrete Roads and Pavements. 211 



these requirements shall be rejected. All cement to be used 
on the work shall be suitably protected from exposure to 
moisture until used. 

9. The ingredients of the concrete shall be thoroughly 
mixed in a mixer approved by the engineer; enough water 
being added to produce a plastic mass that will flush slightly 
under light tamping, but not so thin that the mortar will 
separate from the coarse aggregate. 

10. No retempering of concrete will be permitted, and 
that in which mortar has begun to set shall be rejected. 

11. No concrete shall be laid when the temperature at 
any time during the day or night falls below thirty-five (35°) 
degrees above zero, Fahrenheit. 

Longitudinal expansion joints i/^ inch wide shall be con- 
structed the full length of the pavement, on each side of the 
street next to the curb. The joints shall extend the entire 
depth of the pavement and be filled with Dolarway bitumen 
and coarse sand or grit. Care shall be taken to fill these 
joints fiush with the surface of the pavement, and before the 
wearing surface is applied. 

Transverse expansion joints may be omitted, unless other- 
wise directed by the engineer in charge of the work. 

13. Not less than 10 days after the concrete has been 
laid as above specified, and is thoroughly set and perfectly 
dry, the surface shall be brushed vigorously with a wire broom 
to remove all loose or insecure particles, and immediately 
before applying the bitumen it shall be swept with house 
brooms or fiushed with water until clean. After it is perfectly 
clean and dry there shall be spread over the entire surface a 
layer of Dolarway bitumen, using not less than one-third nor 
more than one-half of a gallon to the square yard, said 
bitumen to be applied at a temperature of not less than 200 
degrees Fahrenheit nor more than 250 degrees Fahrenheit. 

Immediately following the spreading of the bitumen there 
shall be spread over the entire surface a uniform layer of dry, 
clean, sharp sand, or fine washed gravel, or screenings, using 
not less than one (1) cubic yard to one hundred (100) square 
yards of surface. No bitumen shall be applied when the tem- 
perature is below 40 degrees Fahrenheit, and the sand or 
screenings shall be applied while the bitumen is sufficiently 
soft to permit of their becoming thoroughly imbedded in it. 
After the sand or screenings have been spread, the street 
shall be closed to travel for a period of not less than two (2) 
hours, after which time the street may be opened to travel. 

Note. — The thickness of the concrete foundation is not 
specified in the above, nor are the proportions of the materials 
composing it, as local conditions and requirements must de- 
termine these points in each individual instance. The Dolar- 
way Company, however, recommends that the concrete base 
be composed of a mixture not leaner than 1:2:4 and that 
its thickness be not less than 5 inches. 



APPE^^DIX I. 



SPECIFICATIONS FOR LAYING HASSAMITE. 

1. The sub-grade shall be of the same cross section as 
the finished surface, but of less elevation to the extent of 
the proposed pavement. 

2. In places where fill is required, it may be made with 
any suitable material excavated from the improvement. 

All filling must be made in uniform layers not over 6 
inches in depth and each layer shall be thoroughly rolled or 
tamped as may be required to insure a solid bed. 

No material shall be placed in a filled embankment ex- 
cept that which is suitable, whether taken from excavation 
in the road or elsewhere. 

3. The roadbed shall be brought to a solid sub-grade of 
exact cross section, by rolling or tamping as may be required, 
and any material which does not produce a firm foundation 
shall not be permitted in foundation. Any such shall be re- 
moved and replaced by material approved by the engineer. 

Any extra work to be paid for at cost, plus 10 per cent. 
Requirements of Materials. 

4. All cement used on this work must fulfill the follow- 
ing requirements. [Standard Specifications of American So- 
ciety for Testing Materials.] 

5. Sand. — The sand for the foundation shall be clean, 
sharp, and free from clay, loam or organic matter. The sand 
for the wearing surface shall be of such quality as the con- 
tractor may determine. 

6. The foundation may be of stone, slag or screened 
gravel. 

7. All water necessary for the construction of the pave- 
ment shall be furnished free of cost to the contractor by the 
city. 

Hassam Concrete Foundation. 

8. Upon the sub-grade prepared in accordance with the 
specifications for grading, broken stone shall be spread so 
that after rolling or compressing, it shall have a uniform 
thickness of inches. 

9. After the stone has been thoroughly compacted and 
firmly embedded and the voids reduced to a minimum, it shall 
be grouted with a grout of Portland cement and sand, con- 
sisting of two parts sand and one or more parts Portland 
cement, said grout to be mixed in a Hassam Grout Mixer to 
insure the accurate blending of the ingredients. 

(212) 



Concrete Roads and Pavements. 213 

This grout shall be poured upon the foundation until all 
the voids are filled and the grout flushes to the surface — the 
stone to be lightly rolled or compressed during the process 
of grouting, leaving uniform surface. 

10. No concrete shall be laid when the temperature at 
any time day or night falls below 26 degrees F. 

Wearing Surface. 

11. The surface of the concrete so produced shall be 
covered with two layers of bituminous composition, known 
as Hassamite, in one or more substantially equal coats of ^A 
gallon each per square yard. This composition shall be ap- 
plied, when heated, to a temperature of not less than 

degrees F. and not more than 300 degrees F. Immediately 
after being applied the first course of composition is to be 
drifted with screened pea stone, suitable sand or gravel, and 
rolled with a light steam roller; the second course to be 
drifted with pea stone, suitable sand or gravel, thoroughly 
rolled, sufficient sand being added to absorb any surplus com- 
position. 



APPENDIX J. 

TYPICAL SPECIFICATIONS FOR REINFORCED CON- 
CRETE BRIDGE AND CULVERT CONSTRUCTION.* 

Plans and Drawings. 

All concrete masonry shall be built to conform with the 
lines and dimensions shown on the plans and drawings fur- 
nished or approved by the engineer in charge, and which 
are hereby made a part of these specifications- In cases of 
discrepancies between figured dimensions and scale, the fig- 
ured dimensions are to govern. 

Concrete. 

The concrete shall be of the character and mixed in the 
proportion indicated on the plans, or as may be indicated in 
writing by the engineer in charge, or as hereinafter specified. 
All concrete shall be prepared and placed in strict accordance 
with the following specifications and plans, and the instruc- 
tions of the engineer under them. 

Cement. 

The cement shall be of some standard brand of Portland 
cement, satisfactory to the engineer in charge. No cement 
shall be used which, when tested, fails to conform with the 
United States Government specifications for Portland cement, 
as contained 4n Circular 33 of the Bureau of Standards. 
Cement shall be delivered in sacks of 94 pounds net weight, 
and each sack shall be considered as having a volume of 1 
cubic foot. Cement which contains lumps or has been dam- 
aged in any way by exposure to the weather or by other 
cause shall be rejected. 

Sand. 

The sand shall consist of dry, clean, sharp quartz grains, 
and shall not contain more than 5 per cent of clay, loam, or 
other foreign materials. The grains shall be well graded 
and of such size that all will pass a i^i-inch mesh screen, and 
not more than 20 per cent will pass a No. 50 sieve. 

Coarse Aggregate. 

The coarse aggregate may consist of either broken stone 
or gravel. Stone shall be sound, hard, and tough, and broken 
to the sizes hereinafter specified, and when used shall be free 
from foreign material. No weathered or disintegrated ma- 



♦Prepared by Charles H. Moorefield, Highway Engineer, Office 
of Public Roads, Washington, D. C, and published in BuUetin No. 
45 of that office. 

(214) 



Concrete Boads and Paveiiients. 215 



terial shall be used. Gravel shall be composed of hard, 
sound, durable particles of stone, thoroughly clean and well 
graded in size between the limits specified below. 

Classes A, B, and C. — Unless otherwise specially pro- 
vided, there shall be three classes of concrete, known as 
class A, class B, and class C. 

Class A concrete shall consist (by volume) of 1 part of 
cement, 2 parts of sand, 4 parts of coarse aggregate, and 
water- All of the coarse aggregate shall be retained on a 
14-inch mesh screen and shall pass a 1-inch mesh screen. 
Not more than 75 per cent shall be retained on a i/^-inch mesh 
screen, and not more than 75 per cent shall pass such a 
screen. 

Class B concrete shall consist (by volume) of 1 part of 
cement, 2^2 parts of sand, 5 parts of coarse aggregate, and 
water. All of the coarse aggregate shall be retained on a 
i^-inch mesh screen and shall pass a li/^-inch mesh screen. 
Not more than 75 per cent shall be retained on a %-inch mesh 
screen, and not more than 75 per cent shall pass such a 
screen. 

Class C concrete shall consist (by volume) of 1 part of 
cement, 3 parts of sand, 6 parts of coarse aggregate, and 
water. All of the coarse aggregate shall be retained on a 
i^-inch mesh screen, and shall pass a 2i/^-inch mesh screen. 
Not more than 75 per cent shall be retained on a 1^/4 -inch 
mesh screen, and not more than 75 per cent shall pass such 
a screen. 

Mixing. 

The cement and sand shall first be thoroughly mixed dry 
in the proportions specified, on a proper mixing platform. 
Sufiicient clean water shall then be admixed to produce a 
pasty mortar. To the mortar thus prepared shall be added 
the proper proportion of coarse aggregate previously drenched 
with water, and the whole shall be mixed until every particle 
of the coarse aggregate is thoroughly coated with mortar. 
Instead of the above method, a mechanical mixer of approved 
type may be employed. 

Size of Batch. 

Concrete shall be mixed in batches of such size that the 
entire batch may be placed in the forms by the force em- 
ployed within 45 minutes from the time that the first water 
is applied. No concrete is to be prepared from mortar which 
has taken an initial set and would require retempering. 

Placing. 

All concrete shall be carefully deposited in place and 
never allowed to fall from a height greater than five feet. 
Concrete shall never be deposited in running water, and when 
deposited in still water it shall be carefully lowered into 



216 Concrete Roads and Pavements. 



place by means of a chute or by some other approved 
method. 

As fast as concrete is put into place, it shall be thor- 
oughly tamped in layers not more than six inches thick, and 
the portion next to the forms shall be troweled by using a 
spade or by other means to bring the mortar into thorough 
contact with the forms. 

Concrete shall not be deposited when the temperature 
of any of the materials composing it is below 35° F., and 
if during the progress of the work freezing temperature 
threatens or is predicted by the United States Weather 
Bureau, proper precautions shall be taken to protect from 
freezing all concrete laid within the four preceding days. 

Forms. 
Forms shall be so constructed as to continue rigidly in 
place during and after depositing and tamping the concrete. 
If during the placing of the concrete the forms show signs 
of bulging or sagging at any point, that portion of the con- 
crete causing the distortion shall be immediately removed 
and the forms properly supported before continuing the work. 
The amount of concrete to be removed shall be determined 
by the engineer, and the contractor shall receive no extra 
compensation on account of the extra work thus occasioned. 
Forms for exposed surfaces shall be constructed of dressed 
lumber. 

All forms shall be left in place not less than 36 hours, 
and all supporting forms not less than 10 days after the con- 
crete has been deposited. These periods may be increased 
at the discretion of the engineer in charge. 

It is understood that all prices for concrete masonry shall 
include furnishing all materials and properly constructing 
all necessary forms. 

Joints. 
When the work of laying concrete is to be interrupted 
for a period greater than 1 hour and there are no reinforcing 
rods projecting, provision for a joint shall be made in the 
following manner: Square timbers 8 inches by 8 inches, or 
some other suitable size approved by the engineer, shall be 
bedded in the concrete throughout the length of the course 
for one-half their thickness and allowed to remain until the 
concrete has taken its initial set. When the work of laying 
concrete is resumed, the timbers shall be removed and the 
surface thoroughly wet. No joints will be permitted in 
reinforced concrete beams, and in floor slabs the joints shall 
be vertical and parallel to the main reinforcing bars. 

Finish. 
Forms covering surfaces of the concrete masonry which 
are to be exposed shall be removed immediately after the 



Concrete Roads and Pavements. 217 

expiration of the period of time necessary for such forms to 
remain in place, as fixed by the engineer, and all crevices 
which may appear shall be filled with 1:2 cement mortar. 
These surfaces shall then be finished with 1:2 cement mortar 
and a wooden float, so as to present a smooth, neat ap- 
pearance. 

Reinforced Concrete. 

All reinforced arches, beams, floors, parapets, guard rails, 
and all concrete masonry measuring less than 9 inches in 
thickness shall be made of class A concrete, unless other- 
wise specified on the drawings or directed by the engineer 
in writing. 

Abutments and Wing Walls. 

Unless otherwise specified on the drawings or in writ- 
ing by the engineer, class B concrete shall be used for all 
abutments and wing walls, the thickness of which is not less 
than 9 inches- 
Footings and Cut-Off Walls. 

Class C concrete shall be used for all footings and cut-off 
walls, unless otherwise specified on the plans or directed in 
writing by the engineer. 

Steel for Reinforced Concrete. 

Unless otherwise specified on the drawings, all reinforc- 
ing steel shall consist of bars which have been deformed in 
some approved manner. No plain bars will be permitted 
except as shown on the drawings or directed in writing by 
the engineer. 

The steel bars shall have the net sectional area and be 
placed in the exact positions indicated on the drawings. 

Unless otherwise specified on the drawings or in writing 
by the engineer, all reinforcing bars shall be of medium steel 
having an elastic limit of not less than 35,000 pounds per 
square inch, and shall be sufficiently malleable to withstand 
bending cold with a radius equal to twice the diameter or 
thickness of the bar through 180° without fracture. 

When placed in the concrete, the reinforcing steel shall 
be free from grease, dirt, and rust, and it shall be the duty 
of the contractor to provide means for properly cleaning the 
steel. 

Thorough contact of the concrete with every portion of 
the surface of the steel shall be obtained. 
Splicing Reinforcing Bars. 

Unless otherwise specified on the drawings or in writing 
by the engineer, necessary splices in reinforcing bars shall 
be effected by overlapping the ends of the bars a distance 
equal to forty times their thickness or diameter. 



APPE^TDix K. 

SPECIFICATIONS OF NATIONAL ASSOCIATION OF 

CEMENT USERS. 

SIDEWALKS. 

Materials. 

1. Cement. — The cement shall meet the requirements of 
the Standard Specifications for Portland Cement of the 
American Society for Testing Materials and adopted by this 
Association. Standard No. 1. 

2. Fine Aggregate. — Fine aggregate shall consist of 
sand, crushed stone or gravel screenings, graded from fine to 
coarse and passing, when dry, a screen having ^-inch 
diameter holes; shall be preferably of silicious material, clean, 
coarse, free from dust, soft particles, loam, vegetable or other 
deleterious matter, and not more than 3 per cent shall pass 
a sieve having 100 meshes per linear inch. Fine aggregate 
shall be of such quality that mortar composed of one part 
Portland cement and 3 parts fine aggregate by weight, when 
made into briquettes will show a tensile strength at least 
equal to the strength of 1:3 mortar of the same consistency 
made with the same cement and Standard Ottawa sand. In 
no case shall fine aggregate containing frost or lumps of 
frozen material be used. 

3. Coarse Aggregate. — Coarse aggregate shall consist of 
inert materials such as crushed stone or gravel, graded in 
size, retained on a screen having 14 -inch diameter holes; 
shall be clean, hard and durable; free from dust, vegetable 
or other deleterious matter, and shall contain no soft, flat or 
elongated particles. In no case shall coarse aggregate con- 
taining frost or lumps of frozen material be used. The maxi- 
mum size of coarse aggregate shall be such as to pass a 
114 -inch ring. 

4. Natural Mixed Aggregates. — Natural mixed aggre- 
gates shall not be used as they come from the deposit, but 
shall be screened and remixed to agree with the proportions 
specified. 

5. Sub-base. — Only clean, hard, suitable material, not 
exceeding 4 inches in the largest dimensions shall be used. 

6. Water. — Water shall be clean, free from oil, acid, 
alkali or vegetable matter. 

7. Coloring. — If artificial coloring material is required, 
only mineral colors shall be used. 

8. Reinforcing Metal. — The reinforcing metal shall meet 

(218) 



Concrete Roads and Paveme7its. 219 

the requirements of the Standard Specifications for Steel Re- 
inforcement adopted March 16, 1910, by the American Rail- 
way Engineering Association. 

Sub-Grade. 

9. Slope. — The sub-grade shall have a slope toward the 
curb of not less than Vz inch per foot. 

10. Depth,* — (a) The sub-grade shall not be less than 11 
inches below the finished surface of the walk. 

(b) The sub-grade shall not be less than 5 inches below 
the finished surface of the walk. 

11. Preparation. — All soft and spongy places shall be 
removed and all depressions filled with suitable material 
which shall be thoroughly compacted in layers not exceeding 
6 inches in thickness. 

12. Deep Fills. — When a fill exceeding 1 foot in thick- 
ness is required to bring the work to grade, it shall be made 
in a manner satisfactory to the engineer. The top of all fills 
shall extend beyond the walk on each side at least 1 foot, 
and the sides shall have a slope not greater than 1 to 1%. 

13. Drainage. — When required, a suitable drainage sys- 
tem shall be installed and connected with sewers or other 
drains indicated by the engineer. 

Sub-Base.* 

14. Width. — Thickness. — On the sub-grade shall be 
spread a suitable material as hereinbefore stated which shall 
be thoroughly rolled or tamped to a surface at least 5 inches 
below the finished grade of the walk. On the fills, the sub- 
base shall extend the full width of the fill and the sides shall 
have the same slope as the sides of the fill. 

15. Wetting. — While compacting the sub-base, the ma- 
terial shall be kept thoroughly wet and shall be in that con- 
dition when the concrete is deposited. 

Forms. 

16. Materials. — Forms shall be free from warp and of 
sufficient strength to resist springing out of shape. 

17. Setting. — The forms shall be well staked or other- 
wise held to the established lines and grades and their upper 
edges shall conform to the established grade of the walk. 

18. Treatment. — All wood forms shall be thoroughly 
wetted and metal forms oiled before depositing any material 
against them. All mortar and dirt shall be removed from 
forms that have been previously used. 

Construction. 

19. Size of Slabs. — The slabs or independently divided 



*Note. — When a sub-base is required, eliminate Paragraph 
10 (b). When a sub-base is not required, eliminate Paragraphs 
5 and 10 (a). Unless Paragraph 10 (a) is eliminated, 10 (b) is 
void. 



220 Concrete Roads and Pavements. 

blocks when not reinforced shall have an area of not more 
than 36 square feet and shall not have any dimension greater 
than 6 feet. Larger slabs shall be reinforced as hereinafter 
specified. 

20. Thickness of Walk. — The thickness of the walk 
should not be less than 5 inches for residence districts, and 
not less than 6 inches for business districts. 

21. Width and Location of Joints. — A i/^-inch expansion 
joint shall be provided at least once in every 50 feet. 

22. Joint Filling. — The expansion joint filler shall be a 
suitable elastic waterproof compound that will not become 
soft and run out in hot weather, nor hard and brittle and 
chip out in cold weather. 

23. Protection of Edges. — Unless protected by metal, the 
upper edges of the concrete shall be rounded to a radius of 
1/^ inch. 

Measuring and Mixing. 

24. Measuring. — The method of measuring the materials 
for the concrete, including water, shall be one which will 
insure separate uniform proportions at all times. A sack of 
Portland cement (94 lbs. net) shall be considered 1 cubic 
foot. 

25. Machine Mixing. — When the conditions will permit, 
a machine mixer of the type that insures the uniform pro- 
portioning of the materials throughout the mass, shall be 
used. The ingredients of the concrete or mortar shall be 
mixed to the desired consistency and the mixing shall con- 
tinue until the cement is uniformly distributed and the mass 
is uniform in color and homogeneous. 

26. Hand Mixing. — When it is necessary to mix by hand, 
the materials shall be mixed dry on a watertight platform 
until the mixture is of uniform color, the required amount of 
water added and the mixing continued until the mass is uni- 
form in color and homogeneous. 

27. Retempering, that is, remixing mortar or concrete 
that has partially hardened with additional water, will not 
be permitted. 

TWO-COURSE WALKS. 

Base. 

28. Proportions. — The concrete shall be mixed in the 
proportion by volume of 1 sack Portland cement, 2^ cubic 
feet fine aggregate and 5 cubic feet coarse aggregate. 

29. Consistency. — The materials shall be mixed wet 
enough to produce a concrete of a consistency that will flush 
readily under slight tamping, but which can be handled with- 
out causing a separation of the coarse aggregate from the 
mortar. 

30. Placing. — After mixing, the concrete shall be handled 



on Crete Roads and Pavements. 221 



rapidly and the successive batches deposited in a continuous 
operation completing individual sections. Under no circum- 
stances shall concrete be used that has partially hardened. 
The forms shall be filled and the concrete struck off and 
tamped to a surface the thickness of the wearing course 
below the established grade of the walk. After the concrete 
has been thoroughly tamped against the cross forms, they 
shall be removed and the material for the adjoining slab de- 
posited so as to preserve the joint. Workmen shall not be 
permitted to walk on the freshly laid concrete, and if sand or 
dust collects of the base it shall be carefully removed before 
the wearing course is applied. 

31. Reinforcing. — Slabs having an area of more than 36 
square feet, or having any dimension greater than 6 feet, 
shall be reinforced with wire fabric or with plain or deformed 
bars. The cross sectional area of metal shall amount to at 
least 0.041 square inches per lineal foot. The reinforcing 
metal shall be placed upon and slightly pressed into the con- 
crete base immediately after the base is placed. Reinforcing 
metal shall not cross joints and shall be lapped sufficiently 
to develop the strength of the metal. 

Wearing Course. 

32. Proportions. — The mortar shall be mixed in the man- 
ner hereinbefore specified in the proportion of 1 sack Port- 
land cement and not more than 2 cubic feet of fine aggregate. 

33. Consistency. — The mortar shall be of a consistency 
that will not require tamping, but which can be easily spread 
into position. 

34. Thickness. — The wearing course of walk in residence 
districts shall have a minimum thickness of % of an inch, 
and in business districts a minimum thickness of 1 inch. 

35. Placing. — The wearing course shall be placed im- 
mediately after mixing and in no case shall more than 50 
minutes clause between the time the concrete for the base 
is mixed and the time the wearing course is placed. 

36. Finishing. — After the wearing course has been 
brought to the established grade, it shall be worked with a 
wood float in a manner that will thoroughly compact it. 
When required, the surface shall be troweled smooth, but 
excessive working with a steel trowel should be avoided. 
The slab markings shall be made in the wearing course 
directly over the joints in the base with a tool which will 
completely separate the wearing course of adjacent slabs. 
If excessive moisture occurs on the surface, it must be taken 
up with a rag or mop, and in no case shall dry cement or a 
mixture of dry cement and sand be used to absorb this moist- 
ure or to hasten the hardening. Unless protected by metal, 
the surface edges of all slabs shall be rounded to a radius of 
about V2 inch. 



222 Concrete Roads and Pavements. 

37. Coloring. — If artificial coloring is used, it must be 
incorporated with the entire wearing course, and shall be 
mixed dry with the cement and aggregate until the mixture 
is of uniform color. In no case shall the amount of coloring 
used exceed 5 per cent of the weight of the cement. 

ONE-COURSE WALK. 

The general requirements of the specifications covering 
two-course work will apply to one-course work with the fol- 
lowing exceptions: 

38. Proportions. — The concrete shall be mixed in the 
proportion of 1 sack Portland cement to not more than 2 
cubic feet of fine aggregate, and 3 cubic feet of coarse aggre- 
gate passing a 1-inch ring. 

39. Placing and Finishing. — The form shall be filled, the 
concrete struck off and the coarse particles forced back from 
the surface, and the work finished in the usual way. 

40. Reinforcing. — When a single course walk is to be 
reinforced, the metal shall be placed at the middle of the 
section. The minimum amount of metal shall be as speci- 
fied in paragraph 31. 

Protection. 

41. Treatment, — As soon as the concrete has hardened 
sufficiently to prevent being pitted, the surface of the walk 
shall be sprinkled with clean water and kept wet for at least 

4 days. The walk shall not be opened to traffic until the 
engineer so directs. 

42. Temperature Below 35° F. — If at any time during 
the progress of the work the temperature is, or in the opinion 
of the engineer will within 24 hours drop to 35 degrees 
Fahrenheit, the water and aggregate shall be heated and pre- 
cautions taken to protect the work from freezing for at least 

5 days. In no case shall concrete be deposited upon a frozen 
sub-grade or sub-base. 



APPEA^DIX L. 

SPECIFICATIONS OF NATIONAL ASSOCIATION OF 
CEMENT USERS. 

CURB AND GUTTER. 
Materials. 

1. Cement. — The cement shall meet the requirements of 
the Standard Specifications for Portland Cement of the Ameri- 
can Society for Testing Materials and adopted by this As- 
sociation. (Standard No. 1.) 

2. Fine Aggregate. — Fine aggregate shall consist of 
sand, crushed stone or gravel screenings, graded from fine 
to coarse, and passing, when dry, a screen having 14 -inch 
diameter holes; shall be preferably of silicious material, 
clean, coarse, free from dust, soft particles, loam, vegetable 
or other deleterious matter, and not more than 3 per cent 
shall pass a sieve having 100 meshes per linear inch. Fine 
aggregate shall be of such quality that mortar composed of 1 
part Portland cement and 3 parts fine aggregate by weight 
when made into briquettes will show a tensile strength at 
least equal to the strength of 1:3 mortar of the same con- 
sistency made with the same cement and Standard Ottawa 
sand. In no case shall fine aggregate containing frost or 
lumps of frozen material be used. 

3. Coarse Aggregate. — Coarse aggregate shall consist of 
inert materials such as crushed stone or gravel graded in 
size, retained on a screen having i^-inch diameter holes; 
shall be clean, hard and durable, free from dust, vegetable 
or other deleterious matter, and shall contain no soft, flat 
or elongated particles. In no case shall coarse aggregate 
containing frost or lumps of frozen material be used. The 
maximum size of coarse aggregate shall be such as to pass 
a 114 -inch ring. 

4. Natural Mixed Aggregates. — Natural mixed aggre- 
gates shall not be used as they come from the deposit, but 
shall be screened and remixed to agree with the proportions 
specified. 

5. Sub-Base. — Only clean, hard, suitable materials, not 
exceeding 4 inches in the largest dimension shall be used. 

6. Water. — Water shall be clean, free from oil, acid, 
alkali or vegetable matter. 

7. Coloring. — If artificial coloring material is required, 
only mineral colors shall be used. 

(223) 



224 Concrete Roads and Pavements. 

Sub-Grade. 

8. Depth Below Grade. — (a) Concrete Curb — When a 
sub-base is required, the sub-grade shall not be less than 30 
inches below the established grade of the curb. 

(b) Concrete Curb and Gutter. — When a sub-base is re- 
quired, the sub-grade shall not be less than 11 inches below 
the established grade of the gutter. 

9. Preparation. — All soft and spongy places shall be re- 
moved and all depressions filled with suitable material, which 
shall be thoroughly compacted in layers not exceeding 6 
inches in thickness. 

10. Deep Fills. — When a fill exceeding 1 foot in thick- 
ness is required to bring the work to grade, it shall be made 
in a manner satisfactory to the engineer. 

11. Drainage.— When required, a suitable drainage sys- 
tem shall be installed and connected with sewers or other 
drains indicated by the engineer. 

Sub-Base. 

12. Thickness, (a) Concrete Curb. — On the sub-grade 
shall be spread a material as hereinbefore specified, which 
shall be thoroughly rolled or tamped to a surface at least 24 
inches below the established grade of the curb. 

(b) Concrete Curb and Gutter. — On the sub-grade shall 
be spread a material as hereinbefore specified, which shall be 
thoroughly rolled or tamped to a surface at least 6 inches 
below the established grade of the gutter. 

13. Wetting. — While compacting the sub-base, the ma- 
terial shall be kept thoroughly wet and shall be in that con- 
dition when the concrete is deposited. 

Forms. 

14. Materials. — Forms shall be free from warp, and of 
sufficient strength to resist springing out of shape. 

15. Setting. — The forms shall be well staked or otherwise 
held to the established lines and grades, and their upper 
edges shall conform to the established grade of the curb or 
curb and gutter. 

16. Treatment. — All wood forms shall be thoroughly 
wetted and metal forms oiled before depositing any material 
against them. All mortar and dirt shall be removed from 
forms that have been previously used. 

Construction. 

17. Dimension of Curb. — The section of the curb shall 
conform with that shown in Fig. 1. The thickness at the base 
shall not be less than 12 inches, and at the top not more than 
G inches, with a batter on the street side of 1 to 4. 

18. — Dimensions of Curb and Gutter. — The sections of 
the combination curb and gutter shall conform with that 
shown in Fig. 2. The depth of the back of the curb shall 



Concrete Roads and Pavements, 225 

not be less than 12 inches and the depth of the face not less 
than 6 inches. The breadth of the gutter shall not be less 
than 16 inches nor more than 24 inches. 

19. Size of Sections. — The curb and gutter shall be di- 
vided into sections not less than 5 nor more than 8 feet long 
by some method which will insure the complete separation 
of the sections. 

20. Section at Street Corners. — The construction of the 
combination curb and gutter at street corners shall conform 
with that shown in Figure 3. The radius of the curb shall 
not be less than 6 feet. 

21. Width and Location of Joints. — A i/^-inch expansion 
joint shall be provided at least once in every 150 feet. 

22. Joint Filler. — The expansion joint filler shall be a 
suitable, elastic, waterproof compound that will not become 
soft and run out in hot weather, nor hard and brittle and chip 
out in cold weather. 

23. Protection of Edges.^Unless protected by metal, the 
upper edges of the concrete shall be rounded to a radius of 
^2 inch. 

Measuring and Mixing. 

24. Measuring. — The method of measuring the materials 
for the concrete, including water, shall be one which will in- 
sure separate uniform proportions at all times. A sack of 
Portland cement (94 pounds net) shall be considered 1 cubic 
foot. 

25. Machine Mixing. — When the conditions will permit, 
a machine mixer of a type which insures the uniform pro- 
portioning of the materials throughout the mass, shall be 
used. The ingredients of the concrete or mortar shall be 
mixed to the desired consistency and the mixing shall con- 
tinue until the cement is uniformly distributed and the mass 
is uniform in color and homogeneous. 

26. Hand Mixing. — When it is necessary to mix by hand, 
the materials shall be mixed dry on a watertight platform 
until the mixture is of uniform color and the required amount 
of water added, and the mixing continued until the mass is 
uniform in color and homogeneous. 

27. Retempering, that is remixing mortar or concrete 
that has partially hardened, with additional water, will not 
be permitted. 

TWO-COURSE CURB AND CURB AND GUTTER. 

Base. 

28. Proportions. — The concrete shall be mixed in the 
proportion of 1 sack Portland cement, 2^ cubic feet fine aggre- 
gate, and 5 cubic feet coarse aggregate. 

29. Consistency. — The materials shall be mixed wet 
enough to produce a concrete of a consistency that will flush 



226 Concrete Roads and Pavements. 

readily under slight tamping, but which can he handled with- 
out causing a separation of the coarse aggregate from the 
mortar. 

30. Placing. — After mixing, the concrete shall be handled 
rapidly and the successive batches deposited in continuous 
operation completing individual sections. Under no circum- 
stances shall concrete be used that has partially hardened. 
The gutter forms shall be filled and the concrete struck off 
and tamped to a surface the thickness of the wearing course 
below the established grade of the gutter. The concrete for 
the curb shall be placed and tamped so as to permit of the 
application of the required wearing course to the face and 
top so as to bring the work to the established line and grade 
of the curb. The work shall be executed in a manner which 
will insure perfect joints between abutting sections. Work- 
men shall not be permitted to walk on freshly laid concrete, 
and if sand or dust collects on the base, it shall be carefully 
removed before the wearing course is applied. 

Wearing Course. 

31. Proportions. — The mortar shall be mixed in the man- 
ner hereinbefore specified in the proportion of 1 sack Portland 
cement and not more than 2 cubic feet of the fine aggregate. 

32. Consistency. — The mortar shall be of a consistency 
that will not require tamping, but which can be easily spread 
into position. 

33. Thickness. — The wearing course of the gutter and top 
and face of the curb shall have a minimum thickness of % of 
an inch. 

34. Placing. — The wearing course shall be placed imme- 
diately after mixing, and in np case shall more than 50 min- 
utes elapse between the time the concrete for the base is 
mixed and the time the wearing course is placed. 

35. Finishing. — After the wearing course has been 
brought to the established line and grade, it shall be worked 
with a wood float in a manner which will thoroughly compact 
it. When required, the surface shall be troweled smooth, but 
excessive working with a steel trowel shall be avoided. The 
section markings shall be made in the wearing courses di- 
rectly over the joints in the base with a tool which will com- 
pletely separate the wearing courses of adjacent sections. If 
excessive moisture occurs on the surface, it must be taken up 
with a rag or mop, and in no case shall dry cement or a mix- 
ture of dry cement and sand be used to absorb this moisture 
or to hasten the hardening. The edge of the curb on the 
street side and the intersection of the curb and gutter shall 
be rounded to a radius of about iy2 inches. All other edges 
shall be rounded to a radius of % inch unless protected by 
metal. 

36. Coloring. — If artificial coloring is used, it must be in- 



Concrete Roads and Pavements. 211 

corporated with the entire wearing course and shall be mixed 
dry with the cement and aggregate until the mixture is of 
uniform color. In no case shall the amount of coloring used 
exceed 5 per cent of the weight of the cement. 

One-Course Curb and One-Course Curb and Gutter. 
The general requirements of the specifications covering 
two-course work will apply to one-course work, with the fol- 
lowing exceptions: 

37. Proportions. — The concrete shall be mixed in the pro- 
portion of 1 sack Portland cement and not more than 2 cubic 
feet of fine aggregate, and 3 cubic feet of coarse aggregate 
passing a 1-inch ring. 

38. Placing and Finishing. — The forms shall be filled, 
the concrete struck off and the coarse particles forced back 
from the surface, and the work finished in usual way. 

Protection. 

39. Treatment. — As soon as the concrete has hardened 
sufficiently to prevent being pitted, it shall be sprinkled with 
clean water and kept wet for at least 4 days. The work shall 
not be opened to traffic until the engineer so directs. 

40. Temperature below 35° F. — If at any time during 
the progress of the work, the temperature is, or in the opinion 
of the engineer will within 24 hours drop to 35 degrees 
Fahrenheit, the water and aggregates shall be heated and 
precautions taken to protect the work from freezing for at 
least 5 days. In no case shall concrete be deposited upon a 
frozen sub-grade or sub-base. 



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A LL developments 
in regard to 
Concrete Roads and 
Pavements are 
carefully recorded 
in this journal. 




Three 

Years 

for 

$1.00 



THE CEMENT ERA is the favor- 
ite Cement Journal. Why? 
Because it is out on the skirmish 
line all the time — fighting your battles, 
keeping you posted on new develop- 
ments, telling you how to make more 
money out of your business. It is not 
written by office theorists, but by men 
who are actually in close touch with 
the field. The best journal for the man 
who wants to keep in touch with the 
progress of concrete road making. 



The Cement Era Publishing Co. 

1207 Morton Building CHICAGO 



Cement Pipe 
and Tile 



By E. S. HANSON 





Table of Contents 


I. 


Introduction. 


II. 


Advantages of Cement for Pipe and Tile. 


III. 


Concrete Pipe Sewers. 


IV. 


Pipe for Pressure Service. 


V. 


Concrete Pipe for Culverts. 


VI. 


Establishing a Plant. 


VII. 


Materials Required. 


VIII. 


Methods of Manufacture. 


IX. 


Curing. 


X. 


The Matter of Costs. 


XI. 


Some Tests of Pipe and Tile. 


XII. 


Machines and Systems on the Market. 




PRICE $1.00 



THIS VOLUME covers a field all its own. The 
rapid development of this branch of the industry 
has given rise to many calls for information 
along these lines — and this book is the result. The 
author has perhaps visited more plants for the manu- 
facture of these products than any other one person, 
and has spent much time in investigating the subject 
on which he writes. He has endeavored to answer 
the many questions which come up in regard to these 
subjects and to answer them from the actual experi- 
ence of men in the business. 

The Cement Era Publishing Co. 

1207 Morton Building CHICAGO 




KENT PRECISION MIXERS 

Produce concrete of the highest quahty at the lowest possi- 
ble cost. They are the most economical mixer made for 
mixing concrete for street paving, curb and gutter, highway 
bridges, foundations, retaining walls, etc. The illustration 
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plate, reversible mixing shaft, spur gear drive, also with 
traction operating in either direction. 

It is the Last Word in Concrete Mixers 
Write for catalog, giving full information, to 

THE KENT MACHINE COMPANY 

318 North Water Street KENT, OHIO 




Baker Armored Joints 

for Concrete Roads and Pavements 

These Joints, and the Installation Bar with 
which they are so readily placed, are the invention of 
a practical builder of concrete roads and pavements. 
They have been installed in about a million and a half 
yards of concrete roadway, notably the work in Wayne 
County, Michigan, and have never failed. 




Here is what Mr. Edward N. Hines, member of the Wa^r\e 
County Highway Commission, sa^s of them: 

"The only surface repair required on our concrete 
roads has been on the roads first constructed, where 
the joints were not protected with the armor plates. 

"By the use of armor p'ates we have practically over- 
come the wear at the joints, which are the weakest 
points in the concrete road, besides securing a smooth, 
even, continuous finish." 

These joints consist of two armor plates of 3/16 inch 
soft steel, 23^2 inches wide, provided with shear mem- 
bers which tie them securely to the concrete. Between 
these armor plates, and extending to the subgrade, are 
one or more thicknesses of asphalt felt. 
The joints are curved to the crown of the roadway, 
and are assembled by means of the special Installation 
Bar furnished on each job. This bar insures accurate 
and economical placing. 

Baker Joints add years to the life of a roadway, 
at a cost of only about 5 cents per square yard. 

The R. D. BAKER COMPANY 



73 HOME BANK BUILDING 



DETROIT. MICHIGAN 




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Critical Inspection 

Fails to T)evelop a Defect in 

Our Wheelbarrows 




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The Toledo Wheelbarrow Co, 

Wheelbarrows and Scrapers 



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Toledo, O., U.S.A. 




Hassam Pavement on Massachusetts 
State Highway at Spencer, Mass. 

Laid in 1906. Photo 1912 



Hassam Pavement is the ideal pavement for all conditions. It com- 
bines the maximum strength of a necessary foundation and embodies 
about 20% more stone as a wearing material throughout the entire 
mass than any other known method of concrete construction. Our 
Compressed Concrete with Bituminous Wearing Surface is the best 
form of pavement for all medium and light traffic, it is noiseless, re- 
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For heavily travelled streets our Hassam Granite Block Wearing 
Surface is the best known form of pavement. 



A handsome hand book on Hassam Pavements 
will be sent on request 

Hassam Paving Company 

Worcester, Mass. 



GOOD ROADS NEED GOOD BRIDGES 




LUTEN UNIT 
TRUSSES 



GIVE 

To the ENGINEER— Insmsince that the steel goes into 
the concrete as he designed it. 

To the CONTRACTOR— A reinforcement at a reasonable 
cost and a unit easily handled. 

To the WORKMAN— Ease in work and the certainty that 
it is correctly placed in the concrete. 




The National Concrete Company 

INDIANAPOLIS. INDIANA 



Write for Booklet " H " giving tables and Specifications 
for Highway Bridges. 




The SIMPLEX Improved Mixer 



combines the good features of both batch and 
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The best feature of Batch Mixers is the rolling 
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The SIMPLEX has a powerful low-down steel 
frame and trucks, a three-part hopper, and has 
any capacity up to ten yards per hour. Is fully 
guaranteed, and sent on trial. 

Write for catalog and full information. 



THE MILES MANUFACTURING COMPANY 

316 E. Franklin Street -:- JACKSON, MICHIGAN 




Studying the 
National Problem 

Good Roads 



Leads to the inevitable con- 
clusion that satisfactory roads 
must be reasonable in cost, low 
in maintenance charges and per- 
manent. Large expenditures for country road and city street 
improvements are not justified when the pavements afford 
only temporary relief — when they are costly in upkeep and 
obsolete under traffic conditions of today. 

In Wayne County (Detroit) Michigan concrete has been 
adopted as the type of road best answering modern re- 
quirements. Concrete makes ideal roads — low in initial 
cost — free fi-om heavy maintenance charges, durable, 
dustless, clean and permanent. 



Write us for free booklets, describing CON- 
CRETE ROADS— Fifth and Sixth Annual Re- 
ports of the Wayne County Road Commissioners 

Universal Portland 
Cement Co. 




Alpha Portland Cement 

The Recognized Standard American Brand 
Annual Output; 7,000.000 Barrels 

Works : 

Two plants at Alpha, N. J., 70 miles west of New 
York City, on Lehigh Valley R. R. 

Two plants at Martins Creek, Pa., 80 miles west of 
New York City, on P. R. R., D. L. & W. R. R., 
and L. & N. E. R. R. 

One plant at Manheim. W. Va., on M. & K. and 
B. & O. R. R. 

One plant at Catskill, N. Y., 100 miles north of 
New York City, on N. Y. C. & H. R. R. R. and 
Hudson River. Boat shipments direct to all Barge 
Canal points. Atlantic Coast and Foreign Ports. 

ALPHA is guaranteed to pass all Standard, 
State and Government Specificafions 



Used Extensively in State Highway Work 

Prompt Shipments Guaranteed 



Alpha Portland Cement Co. 

General Office 

EASTON, PENNSYLVANIA 

Branch Offices 

Boston Savannah Buffalo Pittsburgh 

Chicago Baltimore Philadelphia New York 




Could you reduce your 
charging labor to 1 man 
and still do the same 
amount of work? 



YOU 
COULD 
IF YOU 
HAD 



'^The STANDARD'' Mixer 

With CART CHARGER 

The greatest time and money saving Road 
Paving Mixer ever offered to the contractor. 

The materials for one entire batch are loaded in carts at the 
material piles and pulled to the mixer by a simple hoist with 
cable attachment. The carts are guided to and from the mixer 
by one man. Only one operation required to charge the mixer. 
No high charging platform or complicated side loader. Cut your 
charging labor 80% and do twice the work. Can be equipped 
with distributing chute and reverse traction. 

SEMI AUTOMATIC DISCHARGE— OPEN DRUM. 

Let us show you how we have saved thousands of dollars for 
hundreds of contractors. 

" The STANDARD " regular machines have a low charging 
platform only two feet high and is attached to the mixer. 

The Standard Scale & Supply Co. 






YOU CAN EASILY 

DO MORE WORK, IN LESS TIME, 
AT BIGGER PROFITS 

because with the Koehring Special Street Paving Mixer one 
man thoroughly mixes, delivers to a distance of 20 or 30 feet 
and spreads the full contents of the drum in one minute's time 
without leaving the machine The bucket immediately and auto- 
matically returns to the drum to repeat the operation, thereby 
producing an almost continuous flow of concrete from the ma- 
chine to any desired spot of the work on either side. 

If you want to win more contracts, and if you desire to 
more satisfactorily and speedily complete each job at bigger 
profits, to yourself, get a Roehring. 

Koehring Machine Company, 
Milwaukee, Wis. 





This is the Koehring Street 
Paving Mixer equipped with 
twenty-foot special concrete 
delivery boom and bucket — the pioneer and most satis- 
factor\ street mixer \n the world — often imitated but 
never duplicated. 




THE KOEHRING 

PRODUCES MORE AND 
BETTER CONCRETE 

Eor Less Money and with Less Cement 

BECAUSE 

with every rotation of the Koehring drum the entire batch is 
many times cut through from ihe bottom, pressed and folded 
over upon itself with a criss-cross, kneading, squeezing motion 
and a raking from end-to-end action that means more thorough 
and more rapid mixing than any other machine on the market. 

The Koehring does three kinds of mixing at once — and every 
one diametrically opposed to the other, thus causing a cataract 
flow from top and sides against the inner end of the discharge 
chute plate— always at right angles to the other mixing— thus 
creating a better mix than is possible through any other method 
and consequently effecting a greater saving in cement. 

The Koehring is the only machine that does it because it is 
the only machiae that can do it. 

Illustrated booklet on request. 



City 
Pavements or 

Country 
Roads of 

concrete or hot bitum- 
inous mixtures can be 
Inid at a greater mar- 
fin of profit with a 

Koehring 
Street Paving 
Mixer. 



KOEHRING MACHINE COMPANY 



GENERAL OFFICES AND WORKS 

MILWAUKEE. 
WISCONSIN, 





The Koehring Street Panng 

Mixer holds the biggest 

records. 

Built in three sizes and two styles— for concrete 
only or both concrete and bituminized mixturea* 




Ever Wonder Why Cube Mixers 
Were Selected for the Wayne O 
County Concrete Road Jobs • 

Remember there are nine Austin Improved Cube Special 
Street Mixers in the main mixing plant, on this most notable 
concrete road construction in America, and here's the very 
good reason why they were selected by the commission: 



"We have purchased mixers which are provided with 
a boom eighteen feet long, which extends to the rear, 
and can be easily revolved about the axis to positions 
varying 180 degrees. On this boom a bucket is run 
back and forth, and in it the mixing product is con- 
veyed from the mixer to the road. On account of the 
movability of the boom, the concrete is deposited 
wherever wanted, and the expense of six or 
eight men to haul the concrete in carts from the 
machine to the place required is reduced to two." 



Men such as these, acting for the public interest and with 
the entire market at their disposal, do not buy a mixer with- 
out investigation. Our mixer has probably been subjected 
to more exacting tests than any other machine on the 
market; and the more it is tested, the more it is used. 



The Austin Cube Drum 

of the Austin Improved Cube Mixer gives it a dis- 
tinct mixing principle. This CUBE principle as 
applied to concrete mixing was one of the first ever 
devised and nothing else has been able to excel it in 
simplicity, thoroughness of mix, rapidity and ease of 
handling. The entire absence of internal mechanism 
prevents any possibility of clogging and renders the 
drum easy to clean. 

In an AUSTIN CUBE DRUM the batch is treated 
throughout a s a 
unit. Not a parti- 
cle escapes. The 
whole batch is 
sifted six times in 
each revolution of 
the drum. The 
mixing is done by 
kneading and not 
by stirring. Made 
in sizes from 2^ 
to 64 cubic feet. 

Send for 
Catalog No, 20 




Municipal Engineering & Contracting Co. 

NEW YORK OFFICE, 90 West Street 
Main Office, Railway Exchange 

CHICAGO. ILL. 



New England Agent 
Southwestern Agent 



Dyar Supply Co. - - - - Cambridge, Mass. 
Wyle Mfg. Co. ------ Oklahoma City 



Western Pennsylvania Agent: J. S. Beckwith 



Pittsburgh. Pa. 



Pacific Coast Aaents- The Lansing Co. - ----- San Francisco 

PaciticUoast Agents. The Beebe Co. -------- Portland 



AGENTS WANTED IN OPEN TERRITORY 



BLAW STEEL FORMS 

For Sidewalk Curb, and Curb and 
Gutter Construction will increase your 

PROFITS 30 % 




Some Reasons WHY 

RT AW ^TFFT FORM^ ^ill not wear out. They are 
DI^/ifT OlLl^L runiTlJ simple, light but very rigid. 
Easy to operate. No complicated parts to lose or get out of 
order. Easily and quickly set up. Can be taken away and 
moved forward to new position in about one-tenth the time 
and with about one-tenth the labor that it takes with the 
old method of wood Forms. No measuring or sawing. 
Perfect alignment obtained. No bracing required. Can be 
operated by unskilled labor. Lumber bill entirely eliminated. 
No maintenance expense. They are indestructible and 
will last for years. The same Forms can be used on 
Sidewalk Curb, and Curb and Gutter Construction. 

Write for Bulletin 47-A 
on Sidewalk, Curb and Gutter Construction 

We design and build Blaw Steel Forms for every type 
of Concrete Construction. 

BLAW STEEL CONSTRUCTION CO. 

General Offices — Pittsburgh, Pa. 
New York, 165 Broadway ChicagO, PeoplCS GaS Bldg. 




7-Mile Concrete Road, Cedar Point, Ohio 

W. S. PACE, CHICAGO, CONTRACTOR, USING MEDUSA 
PORTLAND CEMENT ON THE CEDAR POINT SPEED- 
WAY, THE LONGEST CONCRETE ROADWAY IN OHIO 



Medusa Gray Portland Cement 

is guaranteed to be a high-testing Portland, passing standard 
specifications, and is unsurpassed in fineness, strength and uni- 
formity. Factories are located at Bay 
Bridge, O., Syracuse, Ind., and Dixon, 
111., from which shipments can be made 
promptly. We solicit your inquiries for 
prices. 

2,500,000 BARRELS MEDUSA GRAY 
PORTLAND CEMENT SOLD YEARLY 



Write for free samples and illustrated booklets of 

MEDUSA GRAY PORTLAND CEMENT 
MEDUSA WHITE PORTLAND CEMENT 
MEDUSA WATERPROOFING 
MEDUSA WATERPROOFED CEMENTS 
(Gray and White Portland) 

SANDUSKY PORTLAND CEMENT CO. 

SANDUSKY, OHIO 





PREPARING AN OLD ROAD FOR RE-SURFACING 



THE best, quicker and cheapest way is by means 
of a Huber Roller with Scarifier attached. You 
can hitch a grader on also if you wish, and do your 
scarifying and grading at the same time. Then detach 
the grader, raise the scarifier clear of ground, and use 
the roller to finish preparing the new surface. This is a 
proposition worth investigating by any road or ^reet 
contractor. 

The scarifier is operated by fteam power, an inde- 
pendent cylinder being placed beneath the boiler for that 
purpose. A ftraight lever close to operator's hand raises 
or lowers spikes. Adtion is instantaneous. 

THE HUBER MANUFACTURING CO., Marion, o. 




A SHALLOW CUT— A PERFECT GRADE— HANDLED AT A PROFIT 

THE MARION REVOLVING SHOVEL 

is now taking the place of hand- 
labor for road and street work. (Note 
the shallow cut and perfect grade in 
the above picture.) 

These small shovels can be operated 
by one man. They are self propell- 
ing, and mounted on either traction 
wheels or railroad trucks, as desired. 

Write for information 



THE MARION STEAM SHOVEL CO. 



MARION, OHIO, U. S. A. 

New York Atlanta 



Chicago 



WAINWRIGHT 

STEEIBOUND CONCRETE CURB 

HAS A RECORD OF FIFTEEN YEARS' USE 



"W4INWRIGHT 
PATENTS" 



WITHOUT A FAILURE 




ABSOLUTELY 
NON-BREAKABLE 

CHEAPER THAN GRANITE 

OVER 

FIVE MILLION 

FEET 

IN USE IN MORE THAN 

FOUR HUNDRED 
CITIES 

IN THE UNITED STATES 



THE WAINWRIGHT 

GALVANIZED STEEL 

CORNER BAR 




HAVING SOLID ROUNDED 
HEAD AND DOVETAILED 
WEB EXTENDING TWO 
INCHES INTO THE CON- 
CRETE ITS ENTIRE LENGTH, 
FORMING CONTINUOUS IN- 
TEGRAL ANCHORAGE, IS THE ONLY BAR THAT CAN 
BE DEPENDED ON TO PERMANENTLY RETAIN ITS 
PLACE IN CONCRETE. 

FROST WILL NOT DISPLACE THE WAINWRIGHT BAR 
AS IT WILL ANY BAR ANCHORED AT INTERVALS 

STEEL PROTECTED CONCRETE CO. 

REAL ESTATE TRUST BUILDING 
PHILADELPHIA, PA. 



We Build 

Universal and Eureka Crushers 

In 25 Sizes. Fully Guaranteed 



The Crushers cover every requirement in the crush- 
ing field. Both stationary plants and mounted outfits for Con- 
tractors and Road Building. Crushing from 3^ in. and finer to 
any desired size, with a capacity of from 5 to 250 tons per day. 

All machines adjusted to produce any desired size 
while in operation. 

We also manufacture a full line of standard elevators 
and screens. 

Write us your requirements, advising kind 
of material, size and amount required per day. 
Our proposion will interest you. 

ADDRESS 



Universal Crusher Company 





The tremendous enthusiasm shown in 
the Big-an-Little Mixers is indicative of 
the exceptional advantages which the 
Big-an-Little Mixer offers 

OUR LOW PRICES AMAZE THE "MIXER WORLD" 

Yes, there's big value in the Big-an-Little Mixer. It will increase your 
cement work profits and knock big holes in expense. 

A "Mix a Minute" whether large or small from this Big-an-Little Mixer- 
Equipped with loader if desired, which doubles capacity. Same device 
can also be used for hoisting, or is furnished on skids without power. 

It's built Hke a Battle Ship to wear forever — without the extras, the 
price boosting, useless features that do not add efficiency to the Mixer. 

It's sold under an Iron Clad Guarantee that is positive protection for 
you, and one price to all. 

It's not a big mixer. 

It's not a little mixer. 

Capacity per batch 43^ to 6 cu. feet. 

It's the mixer that will put dollars in your pocket and give perfect satis- 
faction for years. 

It's simple — compact, durable, good capacity and the price is right. 



THE JAEGER MACHINE CO. 

216 West Rich Street :: COLUMBUS, OHIO 
MIXER DEPARTMENT 




Bull-Dog Batch Mixer 

No. 1-B being used on street work, putting in a Dollar- 
way concrete pavement, by Childs & Sa^vyer, Paving 
Contractors, Kendallville, Ind. 

The kind of mixer with the quaHty and the efficiency in it. 
One that is strongly built for wear and tear. Has many new 
features in charging, mixing and discharging. Not very often 
does one find quality combined with a very low price as in a 
Bull-Dog Batch Mixer. Made in four sizes, 34 yard up. 

^^Crescent'^ Continuous Mixer 



has every advantage of the batch 
portant, profit-producing features, 
that could not be obtained in a 
batch mixer. Is the simplest, 
strongest, most practical and 
handy mixer on the market. Pro- 
portions accurately and mixes 
thoroughly. We guarantee it. 

Write for Catalogues 



Also Make " Crescent" |^ 
Concrete Sewer Pipe Molds 



mixer, and many more im- 



Raber & Lang 
Mfg. Coo 

822 Mill Street 
Kendallville, Ind. 




MIXERS IN ALL STYLES AND SIZES 



the 
Batch Line 

WINNER 

MONEY 
MAKER 

HELPER 



We are specialists in the Concrete Machinery line, and if you are 
in need of a Mixer, Screen, Elevator, Tile or Culvert Molds we 
have them. Our Winner Mixer for its size can't be beat, and at 
the price of $150.00 it is by far the best Mixer for the money. 

Get our Prices and literature describing our line 
before buying and save money. 



Continuous 
line 

Perfection 
No. 1 

Perfection 
No. 2 

Combination 

with 

Elevator 





Perfection No. 1 



THE CEMENT TILE MACHINERY CO 



201 Rath St. 



WATERLOO, IOWA 



The Coltrin 
Continuous -Batch Mixer 




No. 12 Coltrin 



The Automatic Proportioning Hopper 

Delivers exact quantities of the different materials in per- 
fectly measured small batches every stroke of the feed. 

The Measuring Pockets 

are cleaned every stroke of the plunger. 

The Mixing Blades 

revolving in a steel shell cut through the material at the 
bottom and lift and pour it from the side same as the latest 
improved batch mixers. 

Has Direct Gear Drive— 2 Main Gear and 2 Pinions 

No Chains — No Sprockets — No Belt 

No Revolving Parts — No Springs — No Fillers 



Shipped anywhere on trial. 

The Knickerbocker Co., Jackson, Mich, 

Write for Catalog, 



When in search of a Simple and 
Durable Mixer look up the New 

Cream City Mixer 



The Efficient Kind 




BUILT IN FIVE SIZES 

These mixers are so light and compact that they can 
be easily drawn about by one horse, making it convenient to 
move them from place to place where a number of jobs are 
under way in different parts of the same locality. 

Each mixer is equipped with the latest style worm gear 
driven loaders. The drum is made of two semi-steel castings 
bolted together. The drum is driven by a center chain 
drive — the best drive known and requiring least power to 
operate. 

Write for Catalogue and Prices 

Cream City Equipment Co. 

809 Majestic Building - Milwaukee, Wis. 




SENIOR B. MIXER 

PREDETERMINED 
ACCURATE MIXING 

All the material automatically meas- 
ured to the mixer, water added after 
the material is dry mixed and all the 
material given the same amount of 
mixing and a guaranty of uniform 
quality of concrete, is what you get 
with a 

U. S. Standard Concrete Mixer 

Every operation is mechanical and accu- 
rate, no guessing at proportions or mix- 
ing, with half the expenditure for labor. 

R. R. REED, Gen. Sales Agent 
ASHLAND, OHIO 




No "Break 'Downs with 
the Friction Thrives 



The 

Badger 

Concrete Mixer 



No. 

6 



9 cubic ft. load ma-. 

terial; 6 cubic feet 

finished batch. 

Batch Hopper hold- 
ing entire batch. Low charging platform. End discharge. 
Friction drive. Ample engine power, clutch for starting. 

The BADGER No. 3 Concrete Mixer 

Our Badger line includes Badger No.j, friction drive, a 3 cu. 
ft. batch mixer. This is a side discharge mixer on trucks and 
is most convenient for pulling about in building foundations, 
curbing, sidewalk and for small contracts. 
Also, the Badger Water Valve, which discharges the exact 
quantity of water with each batch by only one pressure of the 
lever and is attachable to any mixer. It is a small valve not 
larger than a quart measure but it is positive, accurate and 
perfect. 

Write for Catalog 25 and Agency Proposition 




BADGER CONCRETE MIXER & MACHINERY 
COMPANY, Majestic Building, Milwaukee Wis. 



The Concrete Highway 

■^^■i""" is the ^^■■^™" 



Highway of the Future 

The road officer who makes a stand for 
concrete highways, and gets what he 
stands for, is sure of two things: 

— the best possible road at the right price 
— and freedom from patent litigation 

— essential in the building of concrete 
highways in good cement. 

/-"Chicago AA" 

has stood the test of time and is speci- 
fied by engineers and architects in work 
of greatest importance, and involving 
the expenditure of millions of dollars. 

** Chicago AA" is made in one mill 
and from one quarry only. This ac- 
counts for its uniformity in strength 
and color, and is responsible for the well 
known saying regarding "Chicago AA" 
— "Every Sack the Same." 



Tell us your road 
problem — possibly we 
may be able to assist 
you. Our suggestions 
will be offered free. 

Chicago Portland Cement Co. 
30 No. La Salle Street, Chicago 





TWO 
GREAT 
PAVING 
MIXERS 



The Grand and the Hartwick 
Continuous Mixers 

are ideal for paving construction, sidewalks, curbs, 
culverts and general highway work. The Grand 
has the best proportioning and feeding device to 
be found on any mixer. The Hartwick has a 
double trough, meaning thorough mixing and 
large output. Read what one paving firm writes : 

General Contractors 

Terre Haute, Ind., Dec. 17th, 1912. 
"We have been using the HARTWICK 
mixer for over two years with great satis- 
faction. Our purchase in October of our 
third machine is a pretty good evidence 
of our regard for the HARTWICK. For 
the kind of work in which we have been 
using it — concrete sidewalks and curbing 
— where it is necessary to do a large 
amount of work over considerable terri- 
tory, we do not know of a better mixer." 
— Foulkes Contracting Co. 

These mixers are made in sizes 
to fit a variety of requirements. 
If you need a mixer on high- 
way work, get our catalogs 
before buying. 

Hall-Holmes Mfg. Co. 
502 Oak St.. Jackson, Mich. 





Concrete Road, Wayne County, New York 

The Highway of the Future 

The building of a country road to 
stand the strain of heavy traffic, 
calls for a concrete road, because 
it is economical and permanent. 

There is a difference between value 
and price. In purchasing cement, as 
in other things , the value should have 
first consideration. "Atlas" is. 

"The standard by which all other makes are. measured." 
THE ATLAS »-^"tland CEMENT CO. 

30 BROAD STREET, NEW YORK 

Corn Excti. Bldg. Chicago, 111. 
Morris Bldg. Philadelphia, Pa. Plymouth Bldg., Minneapolis. Minn. 



■I 



illlllllll 



ATLAS 



llltlllH^^^ 




EUREKA 

ROAD MAKER 

The Eureka's remarkable increase in 
sales and popularity are striking exam- 
ples of the one Continuous Mixer that 
has reached the top by sheer force of 
merit. Every purchaser is assured 
of guaranteed service and satisfaction. 

ASK FOR CATALOG EXCLUSIVE MAKERS: 

Eureka Machine Co. 

75 Handy Street Lansing, Mich., U. S. A. 



United States Distributing 


Points 


Atlanta Dallas Fort Wayne 
Cedar Rapids Dayton Kansas City 
Chicago Detroit New York City 
Cincinnati Indianapolis Milwaukee 


Omaha 

Peoria 

Pittsburg 

Salt Lake City 


Minneapolis 






No. 15 Chain Belt Street Paver operated by one 



is absolutely a one man mixer in that all levers for 
operating the entire mixer are on one side. 

TRACTION — full reverse differential with speed 
about one mile per hour either direction. Traction 
controlled by friction clutch and is independent of 
drum drive. Mixer will climb 15% grade. 

POWER LOADER — open end, direct loading from 
ground level. Capacity of machine 60 to 75 batches 
per hour. 

DISTRIBUTING BOOM — works automatically and dumps 
at any point along the boom. Bucket is self closed when under 
discharge chute. Speed of boom bucket 110 feet per minute. 
The boom may be swung at 180 degrees or at right angles to 
mixer on either side of roadway. 

STEEL ROLLER CHAIN BELT DRIVE THROUGHOUT. 

Practically all castings used are of Refined Crucible Ste«l. 

If you are going to be in the market for a Street Paver Mr. 
Contractor we believe it will pay you to investigate the Chain Belt. 

CHAIN BELT COMPANY, Milwaukee 

REPRESENTATIVES IN 40 CITIES 



IS TIME MONEY 
TO YOU? 

Don't Lose Money Tying Up the 
Job for Weeks When Your Concrete 
Mixer Breaks Down. 




The Drive Gear of the "MC" Rail Track Concrete 
Mixer is composed of five interchangeable parts, made 
of the very best materials, but if a tooth should 
should break, one of the segments can be replaced 
in a few minutes without disturbing any other part 
of the machine. Just figure the saving in time and 
money. This is only one of the many advantages of 



<^ 



MC Rail Track 
Concrete Mixers 



They will do " Most Mixing, Least Fixing." 
The mix is absolutely perfect (never varies). They 
contain every known improvement and are posi- 
tively the "last word" in concrete mixers. The 
smoothest running mixers ever built. 



Our new'catalog'will be of 
wonderful help to you in 
buyingf f^af mixer; it's 
yours for the asking. 
Write today. 



Marsh-Capron 
Mfg. Co. 

Main Office— 489 

Old Colony 

Building 




Marsh-Capron Rail Track Mixei 
Side LoadenGrounded 



ith 



Chicago 



SEP 11 Klf 



